nomerci, as I said, it depends on WHAT DOES SHE WANTS. I didn't say: DO NOT confront him because it might push him away. I said: you CAN confront him only when you are ready to lose him. Because no one can predict his reaction. And we cannot advise the girl to leave the jerk since he is outing with other girls, like few have suggested here. This wouldn't be right to give her such advice.
We only can draw for her different types of scenario, and it's up to her to follow the one she likes.
For someone such situation is acceptable, another would get angry like Oryx, and someone would just leave him on the spot. It’s all about how you feel and – more important – what’s your goal.. and hey, nomerci, we have discussed this point, and this is your opinion, that sometimes it's better to shut up in order to keep a status quo.
So again, it’s up to the wife how to deal with this situation, and she has to think carefully before starting acting, WHAT result she wants to get. This is my point.

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"What lies behind us and what lies before us are small compared to what lies within us."
Oliver Wendell Holmes