One of my FH's groomsmen is very close to both of us. It was a no brainer that he would be in our wedding party....until now. His live-in girlfriend (whom he had broken up with at the time of being asked) is a NIGHTMARE. She picks fights with his family (who will be there and are wonderful people), throws screaming fits, makes huge scenes in public, and will MAKE all attention be on her ALWAYS. Not to mention she is viciously mean to my FH's cousin (FH and I are very close with her) simply for being a female friend of the groomsman. How do we tell him that we would still love if he would be in our wedding, but there is no way we will allow her to come. My FH is in full agreement. This will also be far from the first time that someone has talked to him about his GFs terrible behavior. Had we known they would get back together, he wouldn't have been asked. What do we do?