My old roommate had this problem, except she was the girl. The friend decided to give her an ultimatum, and of course, they were no longer friends. A few years later, she did break up with her boyfriend, but since the friend alienated himself, the story doesn't have a happy ending for any of them.Perhaps you should try dating around, or some hobby to take your mind off of her. Ask your best friend to set you up with someone. That way, she won't have her defenses up against you, and there's the chance you can reconnect your friendship like it used to be. Make an effort to get along with her boyfriend in social situations, not for her, but because it's the good decent human thing to do.If she should ever become single, don't drop everything just because of the news. Some girls like the chase. You've already planted the idea of the two of you. If she's interested, she'll let you know.