I’m in love with my bff’s crush

I don’t want that feel this way but I can’t help it. We’ve had a crush on the same guy before and it’s caused problems and I don’t want that to happen again. But the way she talks about him makes me fall more in love and he always stares at me and talks to me. Makes me think he wants me too but I just can’t hurt my friend like that. What should I do?

I’m annoyed with myself.