Personally, it’s not for me. I couldn’t live without my wife and I don’t really want anyone else. Of course, I still find other women attractive, but my wife is my wife, and she’s the constant in my life.
I can understand that from a genetic point of view, men are made to get as many partners as possible. This is a known fact and makes for a nice and healthy genetic heritage.
In my opinion, it won’t take long for his marriage to implode. Usually, situations like these are deal-breakers marriage-wise.