How can I make a guy understand?

well, if he`s been a little, shall we say a little violent at times, be careful. sounds to me he`s a little unstable when it comes to relationships. if you`ve already tried to explain it to him, and he doesn`t get it, maybe you will have to resort to a restraining order. he can still see his child, just not you. hold your ground now, or you will be miserable forever. forever is too short. good luck.... he`s got to grow up.