Forget about the dude, he probably wasn't done with his ex to begin with. As for your "best" friend, you can try to repair your friendship with her but I think you would always have trust issues with her. Honestly, if she was your friend at all, someone whom you share all of the deepest personal stuff with, she wouldn't have told your ex-hubby anything, but she did. If it was me, I would write her off and never speak to her again.