You can't. Listen, you cannot control your bf's behavior. Only he can. There is nothing you can do to "make him" stop cheating. You have to be yourself in any relationship. You cannot change who you are as a person to try and make him do anything. If he is cheating on you, then he probably won't stop. If you confront him & tell him you know, he might stop for now. But, if he cheats once, he will do it again. Do you really want to be in a relationship with someone who is not trustworthy? You deserve better than that. You deserve to be treated with respect. I say dump him and move on. He is the one who will end up regretting what he lost. You will end up regretting only that you did not dump him sooner. Go and find a guy who will treat you like an equal partner. He won't cheat!