religious. breakup. prom

Me and my boyfriend broke up more than a month ago. We still talk still close. We want to be together but things are just confusing because of his religious beliefs... he's Mormon wants married in the temple I'm not and don't want to change and he wants me too, etc. we broke up. He also lives somewhere else 
I was asked to prom by someone else. Should I not go I don't want to hurt my ex or make him mad at me. 
Should I tell him I was asked and talk to him about it?
Should I go?