sticky situation

so a few months ago i met this guy and we started talking but decided not to get into anything to serious since i was going back to school for 3 months. we talked a few times out of the week and everything was fine.  then one night my bestfriend tells me that she likes this guy and she wanna start talking to him so of course i encouraged it. when i found out she liked him i should've said something to her but i DIDNT. i called him immediately and said if you wanted to be with me then you can't have sex with my bestfriend.. well one night they were drunk and THEY HAD SEX. so i stopped talking to him because him and my bestfriend were involved. when i came home for summer break i ended up running into him at a friends house and long story short one day we ended up having sex after getting drunk. i felt bad because my bestfriend was starting to fall for him but then i didn't feel bad because we knew that he had a WHOLE GIRLFRIEND that he's been with for 6 YEARS and he really was community property.. now she found out that we had sex and told me that she doesn't want anything to do with me (we've been bestfriend for 8 years and her son is my Godson) but she still communicates with the guy.. i'm hurt on so many levels i can't even put them into words