I (19F) work as a live-in nanny for my sister (26F) and her husband (31M). My sister, let's call her Lucy, is a workaholic and would frequently travel for her job, leaving my brother-in-law, let's call him Reese, home with the kids. After a particularly hard trip, my sister offered me a position. She gave me free room and board and a decent chunk of spending money if I lived in their spare room and helped with the kids. Honestly, my sister and I weren't that close, but I was sick of my roommates, so I decided to give it a shot.

It was normal for a few months. I helped the kids, did the dishes, tended the laundry, you know, normal live-in stuff. When my sister was in town, she'd help where she could, but she was almost always too busy to lend a hand. I didn't mind. The gig was cushy enough.

Things started to change after I worked for them for about six months. My sister left for a two month work trip in Europe, leaving me and Reese home with the kids as usual. We'd always been friendly with each other. We would watch shows in the evening after the kids were in bed. It was nice to have someone to beat the loneliness, you know?

One night, Reese sat closer to me than usual. I didn't think much of it at the time. The next night, he put his arm around me. It was cold that night, so I didn't say anything. It was nice after all. The night after, his hand found my thigh while we were watching our show. I asked him what he was doing. He asked if I wanted him to stop. I know I should have shut him down, but I didn't tell him to stop. I liked the attention.

It was like that for about a week. He would do things to me that pushed the boundaries, but never crossed the line enough to get me to stop him. He'd hug me from behind while I was doing the dishes, holding his firm body and hard cock to me while I worked. He would pull me into his lap while we watched our shows, touching me over my clothes. He'd walk into my room unannounced, especially after my showers, in hopes of catching me naked. I knew what he wanted. I just wanted to know if he'd do anything about it.

I heard him and my sister fighting over the phone one evening. I knew their relationship was on the rocks long before she left for this trip. My room was next door to theirs and I only heard them having sex once the entire time I had lived here. Either they were extremely quiet, or they weren't fucking. I heard Reese tell her that this wasn't fair, that their family needed her home. I couldn't hear her response, but I knew Reese hung up halfway through. That night he didn't touch me during our shows. I could tell he was upset. I gave him his space.

The next day, he acted like everything was normal. He got up to his usual antics but it felt different. I did the dishes and he hugged me from behind. He pressed himself against me, but this time he started to grind against my ass, showing much more obvious desire than he had before. I asked him what he was doing. He asked if I wanted him to stop. I said no. He held me closer and kissed my neck. I wanted to tell him to stop, that I didn't want this, but that would be a lie.

That night, he put on our shows. He pulled me into his lap. I didn't protest. He gently touched me over my clothes. It felt good. About halfway through the episode, we hit a sex scene. Normally, he and I just sat awkwardly through them, sometimes making comments about how unrealistic it was. This time was different. Something must have snapped in him.

As the scene played, his hand slipped into my pants. My breath hitched. He paused, waiting for me to stop him. I didn't. He pulled my panties to the side. He waited for me to stop him. I didn't. He ran his finger up my folds. He waited for me to stop him. I didn't. He continued like that, pushing my boundaries inch by inch until he had me naked on the couch, his hand covered in my pussy juices.

I told him to fuck me. He didn't hesitate this time. As soon as I gave him the greenlight, his clothes were on the floor and his dick was in me. It was amazing. My head spun as I let him ravage me. He finished inside. I didn't care. I just wanted more.

I wish I could say that was the only time, but it happened more and more. Having sex became our favorite activity. Every night after the kids went to bed, we would fuck like rabbits. It started slipping into our daytime routine. He would stay late after the kids left for school to have a quicky before work. He'd come home during his lunch break to visit me. Sometimes I would suck him off while he ate, but sometimes we would just talk. He was my favorite person in the whole world.

He told me he loved me. I said I loved him too. I meant it.

When my sister came home from her trip, it was hard to stop. They were dysfunctional as ever, but I still got jealous when they would kiss. I knew they were married. I knew I was the homewrecker, not Lucy, but it still hurt to see. I got so used to him being mine.

Reese would still visit me on his lunch breaks. That was the only time we had alone. He would tell me how much he loved me and how much he wished we could be a couple. I told him we couldn't do that to Lucy, but I would still cave and have sex with him anyway.

We kept fucking like that, finding the moments where we knew we would be alone. We had known from the beginning that what we were doing was wrong, but now we just had to be sneakier about it. I knew Lucy would lose her mind if she found out how far we had let this go. Honestly, the thought turned me on. Any time I did get to be with Reese, I rode him like there was no tomorrow. If we were risking getting caught by being together, I wanted it to be worth it.

She went out of town again. He took a full day off work so we could finally catch up. We fucked so much my entire body was sore. After splattering my cunt with his cum for the third time that day, he dropped the bomb. Reese told me he was considering asking for a divorce. Lucy still didn't know we were sleeping together. How would she? She was never around to meet his needs. I don't want to ruin this beautiful family, but I'm sick of hiding my love for my brother in law.

So… Am I the asshole?