Most Helpful Girl
Well I think the right thing to do is to let her decide. And just be there for her no matter what the outcome is. Tell her what you heard and ask what she wants.
I would tell your friend if she says she wants you and doesn't want to get back together with him.
Most Helpful Guy
Don't just step to the side for someone else. You are as entitled to pursue happiness as him and everyone else. Stand your ground and tell him that you are dating her.