Bad Friend?

I have this male friend who is dating a girl that I simply do not trust at all. (She's rude/annoying and a bit two faced). Anyways she doesn't like that me and him are good friends and has put him in a position where he has to choose me or her. If he chooses her then he's not allowed to be my friend anymore but if he picks me then she'll just be super pissed. I don't care to get involved because I think it's dumb but any advice on this type of thing? Lol.