Ask Your LOR About This One

Here's a story posted on a board that I don't quite understand. Maybe you can explain it to me.

A man married a seemingly perfectly normal woman and they have a large for their surroundings family. Along the way they become frum. After the birth of their youngest the woman becomes severely mentally ill. She ceases going to the mikva and allowing her dh to even approach her. He continues to stay married to her because not only was it very questionable if she was fit to accept a get but he loves her and so do the children. In addition they want to not have any problems with shidduchim.

At some point the man goes to the LOR and says that he cannot be without a woman any longer without committing some kind of avera and this is not life. All attempts of family, rav and professionals to talk to the wife are futile. The rav doesn't say yes but he doesn't say no either to the man approaching other women as long as nidda is kept and it is very discreet to not hurt the man's family or the woman. He had several relationships which all ended for the same reason - the woman wanted a man she could marry. He confided to me that if he did not love his he would have killed her. But what bothered him the most is that if any woman he had been with had been found out she would have been a home breaker and a bitch while most would at least tacitly excuse him.

Yeah. So here are my questions.

1. Does halacha really require a man to stay with a psychotic woman? How crazy does she have to be for him not to be able to give a get? Isn't there something where you drop it off with the rav and she picks it up at her convenience? Aren't there medicines these days for crazy people and can't the husband get his wife committed, if she is so nuts? Could this rav have not found some other way out for this family?

2.  Okay, let's say he has no choice but to be married to her. Is adultry really better than masturbation, halachically speaking? Okay, maybe for a man there is no adultry because he can have more than one wife, but morally speaking, wouldn't cheating on your mentally ill spouse be much worse than jerking off?  Does God care about "morally speaking" or does He only care about the strict halacha?

3. They don't want to have problems with shidduchim? WTF? He has a crazy wife whom he can't divorce so he has affairs and he thinks this will be better than divorcing her with regards to his kids' shidduchim? WTF.

4. If he hadn't loved his wife, he would have killed her? Doesn't this just seem like the standard cheating guy routine, with a twist?  My wife's a crazy bitch that I want to kill, but we love her,  she won't give me any and now I have to get myself some on the side. Oh, yeah, my LOR said it's okay. Just so we don't mess up the kids' shidduchim.