When I had problems with my husband I asked my brother if I could stay at his place. My brother is married and lives only with his wife. Before he got married we used to fuck each other. My marriage was already a mess and fucking my brother was an escape, but we stopped since I met his wife, we became best friends. While I was at his place I slept on the living room couch and on this night my brother came to visit me. We did fuck but none of us felt comfortable doing it. I guess he was worried about his wife being in the next room and I was feeling I was cheating my best friend.