Sweetie,
I hate to tell you this, but I think that the sex was probably just "sex-for-the-last-time" sex. This always used to happen with my ex-boyfriend and I. Then I realized that the whole situation wasn't going to work out because I couldn't handle the friends with benefits situation. I really hope you don't let yourself get caught up in this situation...regardless of how good the sex is! Good luck with your situation. You'll get through it...it might take a little while but you will survive!
Jadey