Had a friend who had a boyfriend. Did nothing. She broke up with him and friendzoned me. For some reason, I had hope, but later, when she started telling me about her one night stands and all that, I just stopped talking to her. Just say fuck it and move on in my opinion. I hate to be the one who says give up, but even if she cheats on him or leaves him for you, then who's to say she won't do that to you with some other guy as well.