I think you should try to understand why he does cheat. Ask him honestly to know if it has been his lifestyle a long time back. May be he is not satisfied in bed or simply get bored. Some men love to 'taste' spoilt ladies or battle with lust. Some men are very sexually active that the moment their partner is not close and they are in the mood, they switch to the most available. Try to understand the pattern to it and possibly break the circuit of thinking and action or seek help or prayers.