I [42F] hooked up with my best friend’s brother while she slept in the next room.

I don’t think I can look at her. I need this out of my head.

We’ve been close since school. Her family treated me like theirs. I spent more weekends there than at home. Her older brother K is 32. He moved back after a breakup.

Last weekend was her birthday. We got wrecked at her parents’ place. They were away. Friends left around 2. I was too drunk to go. She passed out in her room. I was on the couch trying to come down enough to sleep.

He came downstairs for water. Talked. Checked on me. I looked at him and he wasn’t “her annoying brother” anymore. Just a man. Attractive. Looking at me like I wasn’t her friend.

I kissed him. He paused. Said she’d kill us. I pulled him onto the couch and he stopped arguing. We had sex there with her door ten feet away. I bit his shoulder to stay quiet. Thin walls.

He was careful. Kept asking if I was okay. Afterward he held me and said it couldn’t happen again. He cared about me. She’d never forgive us. I pretended to agree.

In the morning she made pancakes. We sat there acting normal. She said we were quiet. We blamed hangovers. She bought it.

I’ve been dodging her texts. Not because I regret it exactly. It was one of the closest nights I’ve had. Because I know I’ll do it again. He wrote yesterday that he can’t stop thinking about it. I should shut it down. Protect the friendship. Be decent.

I want him more than I want to do the right thing. That makes me a bad friend. Worse than that.