Most Helpful Guy
You do what feels right? If you want to maintain the friendship, then say to your friend that you'll reschedule. if you want to completely end the friendship, just say so
Most Helpful Girl
I get how its weird however I wonder why he's insisting you not to be friends with her any longer, is he afraid you'd find out something that he told her etc? I think you should be honest with both of them, tell her that you're in a relationship with him again and if that makes her feel weird then perhaps your friendship had run its course, if she stays then okay tell him that you don't see the issue with being friends with her as she is a good one (if she is) you'll keep her at distance but he can't forbid you from hanging with her as he was ultimately in the wrong.