You're doing all the work in this relationship. That's not fair. A relationship is 50-50. Him telling you you're not sexy in jest is just plain mean and nasty as well as uncalled for. The breast comment? Another hurtful tactic and comment. NOT NICE. Perhaps he would cheat. Sure seems like he practically wants to. Who says these things except someone who is already thinking about it? I would ditch the relationship and find someone better. He's not worth all this effort.