I think he is a sex addict. When he's stressed, he gets extremely horny. Example- we have sex on Fri night, I go to sleep, he takes care of business again on his own (I feel the bed shaking), he does it again Sat morning, we have sex Sat night, then again Sunday. Sound a bit much?
And it seems like he's been in a MLC for almost 10 yrs, he hasn't been happy at work for a long time and feels trapped. Combined with some health issues, he's not a real happy person. I've often wondered if he's depressed, but he won't consider that.