hi MasterPlan
i don't believe it is your job to fix this problem. he is a grown man and he must sort out his extra-marital affair.
in my opinion, this is NEVER okay. cheating on his wife is just NOT okay. it doesn't matter how you want to look at it.
i will suggest that you ask yourself this question: if your husband was having an affair, and this man's wife knew about it, would you want them to tell you?
but i am not suggesting that you should be the one to tell his wife what is going on. it's not your job. not your responsibility.
what i am suggesting, is that you should definitely let this man know, in no uncertain terms that you completely disagree with what he is doing and ask him to stop telling you about it. he should stop involving you in his affair
i understand that you are worried about what the family will think of you if you tell his secret. what will they think of you if you keeping his secret, when his secret eventually comes out?
you are carrying a very heavy burden by keeping this man's secrets. i understand he probably feels he has found a way to unburden himself of this secret by sharing it with you. but now you carry his burden for him. i think this is very unfair on you.
love & light
Brendan