<human>: Can you provide a brief overview of the text?

A couple days ago my best friend called me and told me his girlfriend of two years had sex with another man the previous weekend. This was a huge surprise because he was such a great guy to her. He loved her and did everything he could to treat her right. She was my pals first real girlfriend, and he also lost his virginity to her. 
He's really depressed and I don't know what to do/tell him to make him feel better. He talked to her yesterday and she told him she was really drunk and he basically 'took advantage of her'. She is saying he raped her, but she wont do anything about it with the law because she says college athletes can't drink. So she doesn't want it to effect her sports. I think this is a cop out and she is trying to make it seem like she isn't  the one to blame. They had some issues in the past where he found her texting another man, and telling him some really flirty/questionable things. 

What should I tell him/or do to comfort him in the rough months ahead of him? Also, do you think he should stay with her?
<bot>: Friend found out his gf of two years cheated on him. They had issues in the past, but nothing like this. She claims the man raped her. I think its bullshit.