How do you help or learn ..

Ni
How can I help or learn how to cope with my SO having bipolar.. I'm always understanding and patience with him but we were talking about things and he has a anger problem and has been in anger management for the past 5 years. Should I be scared that he would ever hit me? He says he would never hit me but I don't want to say the wrong thing or make him feel like I'm not trying to understand what he goes through in his head please don't be rude I'm genuinely trying to help myself to help him. I told him if he ever hit me I'd leave was I wrong for saying that? When we argue or fight he just walks away but idk I guess I'm just trying to understand what bipolar is and how to help my SO ♥