Honestly I think he deserves to know. I happen to be big on fidelity, loyalty, and honesty myself. I've seen to much shit from my brothers and it disgusts me. But then again If he does stay with you, you have to realize that your giving him a "get outta jail" free card. So basically that one night you and him get into a fight, if he does cheat you really can't "say" anything. But then again he might not ever cheat but again you have indirectly given him a "right" to. So if you can put up with that then tell him. If you feel guilty, tell him. If you feel you can stomach the guilt don't tell him. Basically the only 3 legit probale outcomes that your situation will result in. Buena Suerte Nicole. P.S. - I think she feels pretty guilty as it is, enough guys?