My boyfriend is cheating on me with his personal trainer. I confronted her in a way no one expected.

I tightened the strap on my sports bra, staring at myself in the mirror of the gym’s locker room. The faint hum of the overhead fluorescent lights buzzed in my ears, but my mind was elsewhere. *He’s been acting strange lately.* The thought gnawed at me as I shoved my bag into the locker, my fingers trembling slightly. Kyle was supposed to meet me here an hour ago. He always had some excuse lately—work, traffic, *something*. But I wasn’t stupid. I’d seen the way his eyes lingered on his trainer, Mia, during our last session. The way she’d laughed at his jokes a little too loudly, her hand brushing his arm just a second too long.

I grabbed my water bottle and headed out, the smell of rubber and sweat hitting me as I stepped into the main gym area. It was late, and the place was almost empty. The rhythmic clank of weights echoed through the space, but something else caught my attention—a muffled giggle. My stomach clenched.

*There*. Near the squat racks. The lights were dimmed in that corner, but I could see them. Kyle, his back pressed against the padded wall, and Mia, her body pressed against his. Her hand was on his chest, her head tilted up as she whispered something in his ear. His face was flushed, his eyes dark with something I couldn’t place.

I froze, my heart pounding in my chest. *No. No way.* But then Mia’s hand slid lower, her fingers teasing the waistband of Kyle’s gym shorts, and my stomach twisted. She dropped to her knees in one swift motion, her fingers hooking into the elastic of his shorts.

“Mia—” Kyle’s voice was low, strained, but he didn’t stop her. He didn’t push her away.

I felt like I was going to be sick, but I couldn’t look away. My phone was in my hand before I even realized what I was doing. I hit record, my fingers trembling as I zoomed in on them. Mia’s lips wrapped around him, her head bobbing slowly, her hand still gripping his shorts. Kyle’s head fell back against the wall, his mouth parting in a silent groan.

*God, he looks so…* I swallowed hard, my body betraying me as heat pooled between my thighs. I hated this. I hated her. But I couldn’t stop watching.

Mia pulled back, her lips glistening as she looked up at him with a smirk. “You like that?” she purred, her voice low and teasing.

Kyle’s hands tangled in her hair, tugging her back to him. “You know I do,” he growled, his voice thick with arousal.

I stumbled back, my phone slipping from my hand as I pressed my back against the cold metal of a nearby machine. I felt like I couldn’t breathe. I should have confronted them. I should have screamed, thrown something, *anything*. But instead, I grabbed my phone and ran back to the locker room, my chest heaving.

I locked myself in a stall, my hands shaking as I pulled up the video. I couldn’t believe I’d filmed it. I couldn’t believe I was *watching* it. But as the video played, I felt something shift inside me. My anger melted into something else—something darker, more primal. My fingers slid under the waistband of my leggings, my breath hitching as I watched Mia’s lips move.

“Fuck,” Kyle groaned in the video, his hips bucking forward as Mia took him deeper.

My own fingers found the wetness between my thighs, and I bit my lip to stifle a moan. *This is wrong*, I thought, but I couldn’t stop. I pressed play again, and this time, I let myself imagine it was me. Me, on my knees in front of him. Me, making him groan like that. My body tensed as I came, my breath catching in my throat.

When it was over, I slumped against the stall, my heart still racing. I felt sick, but I couldn’t deny the heat still coursing through me. I unlocked the stall and stepped out, my legs wobbly. The mirror across from me reflected my flushed face, my wild eyes.

*I need to know*, I thought, gripping the edge of the sink. I need to know how far this goes.

The next night, I was back at the gym. I told Kyle I was staying late to work on my form, but I had no intention of lifting a single weight. I hid in the shadows near the cardio machines, my phone ready once again. And sure enough, just as the clock hit closing time, Kyle and Mia appeared.

This time, there was no teasing. No buildup. Mia was on him the moment the door clicked shut, her lips crashing into his as she pushed him against the wall. Kyle’s hands were all over her, groping her ass, pulling her closer. My stomach twisted, but I couldn’t look away.

Mia pulled back, her chest heaving as she yanked Kyle’s shorts down. He stepped out of them, his cock already hard, and Mia turned around, bending over a nearby bench. “Fuck me,” she commanded, looking over her shoulder at him.

Kyle didn’t hesitate. He grabbed her hips, positioning himself before thrusting into her with a groan. I pressed a hand over my mouth, my heart pounding as I filmed them. Mia’s moans echoed through the gym, her hands gripping the bench for support. Kyle’s thrusts were hard and fast, his hips slapping against her ass with each movement.

“You feel so fucking good,” Kyle growled, his hands tightening on her hips.

“Harder,” Mia gasped, her head falling forward. “God, yes, just like that.”

My free hand slipped under my shirt, my fingers tracing circles over my clit as I watched them. I hated myself for it, but I couldn’t stop. My body was on fire, my breath coming in short gasps as I imagined it was me pinned against that bench. Kyle’s hands on my hips, his cock buried deep inside me.

“I’m close,” Kyle groaned, his thrusts growing erratic.

“Come inside me,” Mia panted, looking back at him with a smirk. “Do it.”

Kyle’s hips jerked forward, his body tensing as he spilled into her with a moan. My own orgasm hit me hard, my fingers pressing harder as I came, my body trembling. I slumped against the wall, my phone falling to my side.

When I looked up, they were still there, Kyle leaning over Mia, his lips brushing her neck as they caught their breath. I felt a lump in my throat, but I pushed it down. I couldn’t let them know I was here. Not yet.

I grabbed my phone and slipped out of the gym, the cool night air hitting my flushed skin. I didn’t know what I was going to do with this footage. I didn’t know if I wanted to confront him, to throw it in his face. Or maybe… maybe I wanted to keep watching. Maybe I wanted to see how far they would go.

As I walked home, my mind raced. *What if I join them?* The thought startled me, but it was there, lingering in the back of my mind. What if I didn’t stop them? What if I…

“Hey.” A voice pulled me from my thoughts, and I looked up to see Kyle walking toward me, his gym bag slung over his shoulder. “What are you doing out here?”

I swallowed hard, forcing a smile. “Just… couldn’t sleep. Thought I’d go for a walk.”

He nodded, wrapping an arm around my shoulders. “You’re so cute when you’re tired,” he said, pressing a kiss to my temple.

I bit my lip, my stomach twisting. *What are you hiding?* I wanted to ask. *Who are you really?*

But instead, I leaned into him, letting him guide me home. The night was silent, but my mind was anything but. I didn’t know what I was going to do.

But I knew one thing—this wasn’t over. Not even close.

The next morning, I woke up before the sun even thought about rising. My heart was racing, my mind already replaying the scenes from the night before. I didn’t know what I was doing—or why I was doing it—but I couldn’t stop myself. I needed to see more. I needed to *know*.

I grabbed my phone and slipped out of the apartment, leaving Kyle still asleep in bed. The streets were eerily quiet, the silence only broken by the occasional hum of a car in the distance. My sneakers padded softly against the pavement as I made my way to the gym, my breath visible in the crisp morning air. I knew they’d be there—him and Mia. I didn’t know how I knew, but I did.

When I reached the gym, I used the spare key Kyle had given me months ago to unlock the side door. The gym was dark, the only light coming from the emergency exit signs. I tiptoed through the empty space, my heart pounding so loudly I was sure it would give me away. I headed straight for the storage room, the one place I knew I could hide without being seen.

The storage room was cluttered with boxes and equipment, but it had a small window that overlooked the main gym floor. I settled myself behind a stack of yoga mats, positioning my phone so the camera could capture everything. My hands were trembling, but I forced myself to stay calm. My phone’s battery was almost dead, so I plugged it into the wall, making sure the cord was hidden. I couldn’t afford to miss anything.

It wasn’t long before I heard the sound of the front door opening. My breath caught in my throat as Kyle and Mia walked in, their voices low and hushed. They were already touching each other, his hand on her waist, her fingers tangled in his hair. My stomach twisted, but I couldn’t look away.

“You’re early,” Mia said, her voice sultry as she pressed herself against him.

“Couldn’t wait,” Kyle replied, his hands sliding down to grip her hips. His voice sounded different—deeper, rougher. It was a side of him I’d never seen before.

They moved toward the squat racks, their bodies glowing under the dim lights. Mia was wearing tight leggings and a sports bra that left little to the imagination, while Kyle was in his usual gym clothes. They started with stretches, but it didn’t take long for things to escalate. Mia dropped to her knees, her hands moving to the waistband of Kyle’s shorts.

My fingers instinctively moved to my clit, tracing slow circles as I watched. I hated myself for it, but the sight of them together was intoxicating. Mia pulled down Kyle’s shorts, his cock springing free. She didn’t waste any time, taking him into her mouth with a hunger that made my legs weak. Kyle groaned, his head tipping back as his hands gripped her hair.

I bit my lip, trying to stifle a moan as I pressed harder against myself. The sound of his pleasure, the sight of her mouth working him—it was too much. I wanted to scream, to burst out of the storage room and stop them, but I couldn’t move. I was paralyzed, caught between anger and desire.

Mia pulled away, a sly smile on her lips as she stood up. “Your turn,” she said, pushing Kyle down onto the bench. She straddled him, her hands gripping his shoulders as she lowered herself onto his cock. Kyle let out a low groan, his hands moving to her hips as she began to move.

My breath came in short, shallow gasps as I watched them. Mia’s body was a blur of motion, her hips grinding against him in a rhythm that was almost hypnotic. Kyle’s hands moved to her breasts, squeezing and teasing as she moaned with every thrust.

I couldn’t take it anymore. My fingers moved faster, my body trembling as I tried to stay quiet. The sight of them together, the sounds they made—it was too much. I came with a quiet whimper, my body shaking as I tried to keep my moans silent.

But they didn’t hear me. They were too caught up in each other, their bodies moving together in a rhythm that was both beautiful and devastating. Kyle flipped them over so that he was on top, his hands gripping her hips as he thrust into her. Mia’s moans echoed through the gym, her legs wrapping around his waist as she begged him to go harder.

I watched, my heart pounding as they moved together. The way he looked at her—like she was the only thing that mattered—broke something inside me. I’d never seen him look at me that way.

When they finally came, it was almost too much to bear. Kyle’s body trembled as he spilled inside her, his face contorted in pleasure. Mia’s moans turned into screams as she clung to him, her body arching into his.

They stayed like that for a moment, their bodies pressed together as they caught their breath. Then they cleaned up, their movements slow and languid. Kyle kissed her, his hands tangled in her hair as they whispered words I couldn’t hear. My stomach churned, but I couldn’t look away.

When they finally left, the gym was silent again. I stayed in the storage room, my body still trembling as I tried to process what I’d just seen. I didn’t know what to do—or what to feel. But I knew one thing: I couldn’t stop now.

I waited until the gym was officially closed before I left, the footage safely stored on my phone. My mind was racing, my body still humming with arousal and anger. I didn’t know what I was going to do with the videos, but I knew I couldn’t let this go.

When I got home, Kyle was already there, his back to me as he cooked dinner. “Where were you?” he asked, his voice casual.

I forced a smile, though my hands were still trembling. “Just went for an early morning run,” I lied.

He turned to look at me, his eyes searching mine. For a moment, I thought he knew—that he could see the truth written all over my face. But then he smiled, pulling me into a hug. “You’re amazing,” he said, pressing a kiss to my forehead.

I wanted to scream, to push him away and tell him everything. But instead, I leaned into him, letting him hold me. My mind was racing, but my body was still. I didn’t know what I was going to do, but I knew one thing: this wasn’t over.

Not even close.

The gym was silent, the only sound the faint hum of the fluorescent lights above. I stood in the corner, my heart pounding in my chest, my hands clenched into fists at my sides. I had texted Mia earlier, asking her to meet me here after hours. She had agreed without hesitation, probably thinking I wanted answers, some kind of closure. But I had something else in mind.

The door creaked open, and Mia stepped inside, her gym bag slung over her shoulder. She looked around, her eyes narrowing when she saw me. “Hey,” she said cautiously, setting her bag down. “You wanted to talk?”

I didn’t respond, my body tense, my mind racing. I took a step toward her, and then another, until I was standing right in front of her. She frowned, confusion flickering across her face. “What’s going on?”

Before she could say anything else, I grabbed her by the shoulders and pushed her against the wall. Her eyes widened in shock, but I didn’t give her a chance to react. My lips crashed onto hers, hard and demanding. She made a small sound of surprise, her body stiffening for a moment before she melted into me, her hands tangling in my hair as she kissed me back.

Her mouth was warm, her tongue sliding against mine as the kiss deepened. I could feel her body pressing against mine, her curves fitting perfectly against me. I pulled back slightly, my breath coming in short gasps, and looked into her eyes. She was gazing up at me, her lips swollen, her cheeks flushed.

“What… what are you doing?” she whispered, her voice trembling.

I didn’t answer. Instead, I leaned in again, my lips brushing against her neck, my teeth grazing her skin. She gasped, her head tilting back to give me better access. My hands slid down her body, gripping her hips as I pressed her harder against the wall. She moaned softly, her fingers tightening in my hair.

I could feel the heat radiating from her, the way her body was responding to me. It was intoxicating, the way she squirmed under my touch, the way her breath hitched when I bit down gently on her collarbone. My hands moved to the hem of her tank top, tugging it up until it was bunched under her arms.

She didn’t stop me, didn’t try to push me away. Instead, she arched her back, her breasts pressing against my chest as I pulled the shirt over her head and tossed it aside. Her bra followed, and then my hands were on her bare skin, cupping her breasts, my thumbs circling her nipples until they were hard and sensitive.

Mia’s breath was coming in short, ragged gasps now, her fingers digging into my shoulders as I kissed my way down her body. I dropped to my knees in front of her, my hands sliding down her thighs to the waistband of her leggings. I hooked my fingers under the elastic and pulled them down, along with her panties, until they were pooled at her ankles.

She stepped out of them, her legs trembling as I leaned forward, my lips brushing against the soft skin of her inner thighs. She made a soft, pleading sound, her hands tangling in my hair again as I kissed my way up her legs until my mouth was hovering over her wetness.

I looked up at her, my breath warm against her skin. She was watching me, her eyes dark with desire, her lips parted as she panted. “Please,” she whispered, her voice trembling.

I didn’t make her wait. My tongue darted out, flicking against her clit, and she cried out, her hips jerking toward me. I gripped her thighs, holding her still as I licked her, slow and deliberate, savoring the taste of her. She was so wet, her arousal coating my tongue as I explored her.

Her moans filled the gym, echoing off the walls as I pushed two fingers inside her, curling them against her g-spot. Her body convulsed around me, her nails digging into my scalp as I pumped my fingers in and out, my tongue still working her clit.

“Oh god,” she gasped, her hips rolling against my face. “I’m… I’m gonna…”

I increased the pressure, my fingers moving faster, my tongue circling her clit until she was trembling on the edge. She screamed when she came, her body shattering around my fingers, her thighs clamping down on my head as she rode out her orgasm.

I didn’t stop until she was spent, her body limp and trembling, her breathing ragged. I stood up, my own body aching with need, and kissed her again, my tongue sliding against hers. She tasted like sin, like forbidden desire, and I couldn’t get enough.

“What… what are we doing?” she gasped when I pulled back, her eyes wide and dazed.

I didn’t answer, my hands moving to the button of my jeans. I unzipped them, pushing them down along with my panties, and then I was pressing her against the wall again, my body flush against hers. She didn’t resist, her legs wrapping around my waist as I positioned myself at her entrance.

“Tell me you want this,” I whispered against her lips, my voice low and husky.

“I… I want this,” she gasped, her nails digging into my back. “Please…”

I pushed inside her, slowly, inch by inch, until I was buried to the hilt. She groaned, her head falling back against the wall as I began to move, my hips rocking against hers. She was so tight, so warm, and I lost myself in the sensation, the way her body clung to me as I fucked her against the wall.

Her moans grew louder, her hips meeting mine thrust for thrust as I pounded into her. The sound of skin against skin echoed through the gym, mingling with our gasps and groans. I could feel her orgasm building again, her body clenching around me as I pushed her closer and closer to the edge.

“You feel so good,” she gasped, her fingers digging into my ass as she urged me on. “Fuck… don’t stop…”

I didn’t. My thrusts became harder, faster, until she was screaming my name, her body exploding around me as she came. I followed her over the edge, my own orgasm ripping through me as I filled her, my body shuddering with the force of it.

We stayed like that for a moment, our bodies pressed together, our breathing ragged. Then I pulled out, my legs trembling as I stepped back. Mia slumped against the wall, her eyes half-closed, her body still trembling with the aftershocks of her orgasm.

“What… what happens now?” she whispered, her voice barely audible.

I swallowed hard, my mind racing. “I don’t know,” I admitted, my voice just as shaky. “But… we’re not done. Not yet.”

She looked up at me, her eyes dark with something I couldn’t quite place. “No,” she agreed, her lips curving into a small, knowing smile. “We’re not.”

**For the voiceover,** [click here](https://www.redquill.net/story/3k3lh2-gym-secrets-and-hidden-desires?utm_source=reddit&utm_id=breakingcanon) **and tap the speak button.**