It's not anyone place to juge as we lack a lot of context. Purely basing my opinion on what was said, seeing how many of my friends families got destroyed because of divorce and how the children lives plumeted into depression, I would advocate for staying if the wife feels that the relationship can be mended. It will never be the same, but cutting every ties will do a lot of damage to the children. In a word, I advocate for staying faithful, not indulging in physical love or s** to avoid get stuck with escaltion of commitment with an unapprpriate person, and having the habit of not indulging into the urges may help resisting tha temptation of cheating