How do i let my best friend's wife know that her husband is cheating on her?

You're right to be worried about both people (and the child!) within this marriage. She needs to know about his adultery before he makes her pregnant again, as that would be the most awful thing to happen to all involved; even the mistress! To have a baby in order to cover up his dates, who is this guy?! Your position is difficult: the bringer of bad news used to be killed in ancient societies, but nowadays people can see what you're trying to do, even if it takes some time. If you've talked to the guy several times, and he's not changing his ways, then you should go to the wife. The husband doesn't seem to deserve a chance to make up, as he's obviously not behaving properly. Once you've put together all your courage, go to her and tell her clearly and precisely what you know or have seen, and that you have had a difficult time yourself coping with knowing this secret. It's too late to think that the adultery will pass by itself and that you shouldn't interfere. She might not be grateful to you at the very moment you tell her, but she will be grateful to you in the future. At least you weren't a chicken, like all the others.

I'd tell the guy that he needs to make a choice. He either calls off the affair and goes back to his wife or divorces his wife. Tell him he has 3 months to make a decision and - after that - you're telling his wife if he hasn't made his move. Better watch your back though - this is a great way to get murdered.

Usually I would say mind your business..but she needs to know. Tell the guy either he tells her, or you are going to. Tell him it is not right.

It's none of your business. I'd keep it as simple as that.

JUST TELL HER