AITA for sleeping with my best friends sister
I'm 27 recently broken up with my long term girlfriend after she let a homeless man grab her ass. I was invited out recently to my childhood best friend's (we'll call him Kyle) cottage. I wanted some time to reflect on my long term relationship in the nature so I decided to come visit. One night, we were drinking and his smoking hot sister who I've liked since I was 11 started to feel me up after a couple drinks. I was pretty hesitant but after a couple of beers I couldn't resist. My friend blacked out and so she snuck me into the adjacent house, she was staying in the guest house. It was getting pretty rowdy and she started yelling. Suddenly my friend bursts into the house and punches me in the eye. I've had a black eye for the past 2 weeks.
Am I the asshole in this situation?