If your boyfriend has already cheated on you and you know he will do it again, why on earth would you want to continue this relationship? You say you want to hurt him back without cheating on him. What sort of relationship is it when both people want to hurt each other. You deserve so much more than a cheating boyfriend. Maybe you think that he is as good as you can get. I hope not because you are wrong. I think you need to get rid of this guy so that there is room for someone who is a whole lot better and faithful to you.