Sex with my best friend.

I've been best friends with this guy for 10+ years. We had drunk sex and he took my virginty. I wasn't upset about it. A few months ago it happened again and it almost happened again. He asked if I liked him and I said no. Then he left the room. Remember we had been drinking again. Now I'm confused about why he left the room and if I like him or not. He's my best friend. I don't want feelings to ruin a friendship. Any advice would help me.