I'm a mature, married man who has endured a passionless, sexless marriage for too long. It's so horrible being trapped like this. I care for my family, but go to bed every night with a stone-cold woman in the bed next to me. Every morning I wake up and wonder "will this be the day she decides to express a sexual interest?" And every night I learn she is just as cold as she was the day before.
You wonder why men "cheat"? This is why. Do that and stand a chance of feeling alive again... or wither away to a pile of nothingness.