In all fairness, many people have affairs in order to stay in their marriages... perhaps they are with a spouse who is deeply depressed, or who is stagnant and bringing nothing to the marital table.... maybe both or one party, for whatever reason, is not interested in sex (as opposed to UNABLE to have sex, due to major illness or whatever).
I have known people who had the choice to leave, or to stay in a marriage of convenience..... where there is a commitment to the life and family they've built... not willing to destroy it close to retirement time when it would be financially devastating to both partners... but also unwilling to sacrifice their LIVES. I get that. I still think it is sad.
AND, the truth is, people divorce EVERY DAY and "move on" to new spouses and lives... their kids are grown and "happy" for them..... the don't look back with regret. I certainly don't want to be married to my first husband, though he was a good guy and we got along great!! We truly DID want different things in life..... the problem is.... I "fell in love" with my current husband (infatuation) and was deceitful..... my first husband never knew... but I DID!!! For many years, I justified it with "Well, I could have handled it better, but I didn't do so bad....divorce is messy and at least we didn't have children... we weren't right for each other!" but now I see the bigger picture. I can feel his pain of being DUMPED, without knowing why....
I don't know if WKramer's answers to any of our questions would enlighten us as to our MLCers at all!! And it is not for him to have to defend himself or his LIFE to us..... people do the best they can with the information they've got..... it's HIS life, and if it works for him, then so be it.