How do you deal with your girlfriends crazy ex boyfriend?

His ex girlfriend is crazy? How? If she is stalking him and threatening you every chance she gets then yes, she's crazy. The 2nd woman has no right to confront the ex girlfriend unless she has to defend herself. It is the man's responsibility to handle his ex girlfriend. Obviously he still has strings attached to his ex girlfriend that he has not cut yet. The 2nd woman needs to ask herself if all of the drama is worth dealing with him. Most likely it's not worth it so move on. Find a man who does not have a closet full of skeletons.