He only talks to me when shes not there?

Well his allegiance lies with her. Obviously he likes her as more than just a friend and that is why doing her bidding is more important than being fair to his friends. If I were you I'd wash my hands of both of them. Next time you're in cl with just you and him, let him try and talk to you.... act as if you don't realize he's there. He'll take the hint.