I am very anti-cheating, but there can be a few circumstances where it may... just maybe... be justified. I would have never thought this, but here is what happened to my friend a few years ago (like 10 years ago).
He and his wife have a seemingly good marriage. He is a successful attorney and she is a stay-at-home mom with two daughters. They have a nice house, many friends and all is well. Both had let themselves go a little bit, but they were still very attractive people. At this point, they are in the early thirties. I believe she was actually 29 at the time, since she is two years younger than him (we are buddies from high school).
So one night my buddy and I were out with a few other friends and he is getting kind of drunk. It was during the World Series. He normally doesn't drink a lot, and this was just a guys night out to watch the game, so it was a little odd that he was drunk. He proceeded to tell me that his wife had totally shut him off. Not like the Post-Nuptial Shut-Off thread, but actually told him to his face that she was done with sex forever. She just didn't like it and wasn't going to do it anymore. She told him she would do other things for him (none of them very exciting), but that basically her body was no longer going to be involved. I laughed at first and told him that she was BSing him but he said that she was 100% serious. She wasn't mad at him and she even told him that it had nothing to do with him; she just didn't like sex and didn't like people touching her. In my head, I immediately thought that she must have gone through something in the past, but I never told him that...
So they go through counseling and everything and basically she didn't budge.
So they go a few years and eventually my friend gets busted doing some extracurricular activity with a stripper. Yes, a stripper. So she divorces him and he is basically socially ostracized. He has two daughters and looks like a total sleazeball cheating on his wife with a stripper.
So I have had so many discussions with him about this. He has never told anyone about her refusal to have sex other than the divorce attorney. He wasn't having sex with the stripper, but it was close to sex and it was in a hotel room. His wife does not believe that they were not having sex, but I do believe him because he has no reason not to tell me. He said he really didn't want to deal with paid sex because of the chance that he might get someone pregnant. He chose a stripper because he didn't want to deal with an emotional affair, and had gotten to know the stripper by visiting the strip club numerous times over the years. It sounds really dirty and terrible, but this guy was totally shut off... He is a really nice, intelligent and kind dude. He is also a very good father.
So in this situation, I am not sure what he did was right, but what are you supposed to do? He was like 31 when this all started. 35 when he got caught.
The silver lining is that he started working out and killing it at work and he ended up marrying a younger woman who is very cool. They now have a child and his ex-wife is fat and alone. The real losers in all of this are his daughters, but the new wife is very good to them and they seem to be okay. I don't think they know what really happened, but they are good girls. Hopefully they never find out.
Anyway, long story but it is true and I thought it was relevant.