Ok, this is a weird one for me. I went to visit my best friend in college last weekend for the first time. His ex girlfriend goes to the same school as him and is one dorm floor above him (not by request). I used to really like this girl when I was a freshman in H.S., and my friend knew it, but I never had the balls to ask her out. Senior year my best friend went out with her for a couple months and then after they had sex they became friends with benefits, they just didn't like the whole relationship thing. Anyway while I was up there, me and her got really drunk and started getting really close, touching, etc. SIDENOTE(Meanwhile my friend is passed out in his room). Then I ran back into the dorm hall to get my cigarettes out of her room and *smack* I hit my head on her door jam and ended up in the ER for an hour getting 10 stitches over my right eye. She was great, though, and stayed with me the whole time. When we got back to the dorms we went up on the roof and talked for hours, I really got to know her for the first time. I was ready to call it a night, because my eye was throbbing by now, but then she said she wanted me to walk her to her car to get something. On the way there she ran into a friend and she convinced him to smoke us out, it is amazing the sh"t girls can pull with a smile and a little bit of cleavage. When we were done, it was about 6:30 am, I told her that I was really tired, (but was utterly drunk and stoned as was she) and I was going to go to sleep. She said something about her bed was taken by some guy her roomate was with, but later I found out that was b.s., so I told her she could sleep with me on my (oh so small and oh so uncomfortable) air mattress in the room with my best friend who had just had sex with her two days before and told me about it! Once we got in bed together I convinced myself not to make any moves on her and to just try and go to sleep ASAP. She kept telling me she "wasn't tired" and needed "to go do something" before she could fall asleep. I played it off like it was nothing and just kept my hands to myself. Then she started playing footsie and giggling and gave me some big signs that she wanted sex now. I just kept telling myself I wasn't going to have sex with my best friend's ex and current hook up while he was 2 ft away from me. I finally fell asleep and then she woke me up and told me to go up to her room where the bed was more comfortable. I stayed in my and just went back to sleep. The next day i avoided her until I said goodbye before I left, we just looked at each other for like 5 minutes and I gave her a hug and left.
What should I do? I still really like this girl, but don't want to lose my best friend. Any advice is greatly appreciated, thanks for reading.