What I think happened here is all three of you got drunk, you had a bit of foreplay he got horny and when he came back you were asleep. He, drunk as he is went to your roommate's room. (also note that being drunk doesn't exuse it) What happened between them was in my opinion concensual. Why didn't she call for help when she saw what his intentions are? How did he even get to finger her without her trying to resist or escape or trying to hurt him in anyway to get him to stop? Was there any sign of struggle like scratches on him or bruises on her? Why, when you knocked on the door, you BF came out, but not her why didnt she use this opportunity to confront you both and say what happened and how she was hurt and raped? Why did she speak up about this only the day after, when asked? I know I would! I'm getting sick and tired of girls who have sex with someone, then regret it so it is always up to the male to take responsibility and be called rapist, which in turn can ruin his entire life! If he becomes registered sex offender, he can kiss his opportunities goodbye. And the fact you can't even say this cause someone will allways cry "Don't blame the victim!!!" is mind boggling.
And this of course doesn't exuse him! If you can't handle your drinking - don't do it!!! He can stop drinking now, and your roommate can "forgive" or get over it, cause all the signs point that she partook in what happened, but in my personal opinion the three of you should go your separate ways. He will never be able to look at you without thinking of that night, he can never walk in that appartment without remembering what happened to her, and you and her will never be able to talk normally. So you move on, he can take this time alone and focus on himself and your roommate doesn't have to live with you anymore cause your relationship is now effectively ruined.
if you decide to stay with him, be responsible adult and dont get drunk to points of passing out, don't drink in front of him, and don't hold this over his head like I see some girls tend to do. If you decide to forgive it, don't mention it ever again. If you dont think you can do this - end this relationship and move on. That's my two cents.
Did anyone think that the roommate never said NO? To me it sounds like she wanted it too. Maybe not so drunk as maybe just wanted some strange?
Personally, it sounds like he's making excuses and making up stories. I don't believe him. I think your roommate has the right idea to stay away. I think you should also stay away from this guy. This, to me, seems like an insurmountable problem with no solution except to part ways with this guy. I can't see getting over it.
I too think " that level of drunk is dangerous and ugly " !! If You do 'forgive' Him You should give Him the ultimatum that He MUST quit drinking - ENTIRELY : not just a little, not just occasionally, but Totally !! He may never do such a thing again but it should be HIS consequence and not Your RoomMate's. She should be able to stay comfortably and safely in Her own apartment - and You should not have Him over, not ever as long as She lives there.
Well, that's a biggie. I personally would no longer be with him unless he gave up partying 100 percent from now on. That level of drunk is dangerous and ugly. How is your roommate? How does she feel about this?