I know it HURTS to hear this, but if this guy has not committed to you or to his ex these last five years, then he is not in love with either of you. Neither of you are "the one" for him. Either, he will be a player forever or, when he meets "the one," he will leave both of you and commit to her. If he was happy with you and in love with you, he would WANT to only be with you. But he does not want that. You can't make him want that. I don't know what his issues are, nor does it really matter. As others have already pointed out, the issue here is why you value yourself so little that you are allowing this situation to go on. We teach people how to treat us, and you're teaching this guy that he can treat you poorly and you will put up with it. You deserve better! It might help to go to therapy in order to figure out how to improve your self-esteem and find th kind of relationship you really want.