Has anybody successfully handled a scorned lover and they left them alone?

My ex always is calling me. I try to be nice because she has a son with but lately shes taken it over the top asking me where im going to stay i moved out of her house and staying with a friend and getting my own place at the end of this week. My girlfriend is having her own issues with her ex cause she broke up with him and he wants to fight. me. Why don't ex lovers just move on? Ive always just moved on after i was dumped or dumped somebody, never made a huge deal about it. I can't really solve the problem with my girlfriend ex, he might just need a butt kicking. But obviously i can't hit my ex, if anybody has a logical solution that would solve the problem, please let me know.