Angel wanted to get away.... from her boyfriend that is. He wasn't abusive well not physically at least. King just had anger issues and abandonment problems due to his parents messing him up.
Angel was king's brightspot in the darkness that was his life. King loved angel to death and couldn't go on without her, so he doesn't let her go, not even when they fight and break up which is every other day. Every time angel walks away from him , he finds her and begs for her forgiveness and promises to change, but they both know that change won't last long. Angel knows this but continues to go back to him over and over again, because she loves him.. and he loves her.