I'm going through a real rough patch but even so by drinking, taking drugs and going to party it doesn't seem responsible to be involved in when in a poor state of emotional well being and I do believe in personal responsibility and I can understand why her boyfriend called you a whore but still no matter what your partner does you should always respect them, love and care for them despite what choices they make and so for that he really should apologise because that is really bad.
It sounds like it was possible that you was raped? It would be a good idea to consider reporting it if you want to otherwise if it was cheating then its actually on your boyfriend not to be judgmental and to understand that there might be a problem in the relationship and so to talk things out so that the relationship can improve.
If my girlfriend ever does anything bad I try to find out about her anxieties and worries and what is making her feel insecure regardless of the subject so that I can try to find something to make things better. If my girlfriend ever cheats on me then I will find out why and try to fill any gaps in the relationship that she might be feeling so that she feels confident in the relationship.
You've been on this forum a while and in a way it feels like you're part of the website and not just another regular user. I hope this helps in some way as its not nice to see someone 'I know' go through this.
I really hope you're okay but pm if you need to talk.