How long ago did this all happen? If it was like 10 months ago and still fresh wounds, it's one thing. But if this was a few years ago, they should be over it by now.
I would hope, if it were my friends, that they could put that drama aside for my wedding. But ultimatley, I think you know best. Do you thnk he will start drama with the hubbie? So you think SHE will start drama with ex?