M.H.
I cannot believe how judgemental your husband's other siblings are being!!! Your poor FIL. That's right, I side with him! Your MIL hasn't given him any sex in years, so of course he strayed!!!! ANY MAN will stray if their wife doesn't give them sex for a very long time. That is a fact. Men NEED sex (more than just wanting it, they NEED it). Any man will cheat if he isn't getting any for a long time. Any man. Your FIL wanted to go to marriage counseling w/ your MIL and I assume she said no? Big mistake!!! For one of your husband's siblings to say he is never allowed in her house again is absolutely INSANE. He is not a child molester, he simply got sex from another woman because his wife sexually abandoned him for years. If he was a molester, then he should never be allowed in all of your houses again, but that is not what he is! He simply is a man with sexual needs who desperately wanted to be loved by his wife, but since she refused, he made it happen with another woman. Poor guy. Shame on everyone (except for you) for judging him and siding w/ your MIL. Regarding your husband dealing with this - have him seek therapy.