The problem is that when it finally dawned on him that it wasn't her ovaries that made her a lousy mother, lousy wife, lousy cook, lousy housekeeper, and overall lousy and unpleasant person but the fact that she was born an incompetent and bitter asshole, he couldn't handle having to look at the chaos his being too in love with the idea of having someone cater to his needs to realize that people will say anything to get a meal ticket created. Therefore, he holed himself up in his workshop and left his family at the mercy of the horrible freak he married. Every so often, he shows up to threaten people who dare to get the insane freak more upset.
This, I should think, is why Michael holes up in his attic. I should think that by now, he must realize that Deanna would have been better off marrying Hannibal Freaking Lector than the effeminate, indolent, incompetent, infantile and self-absorbed slug he sees when he shaves of a morning and that it's slowly destroying her dignity and intellect having to raise three children especially when the oldest stopped maturing about the same time Reagan got shot. Rather than look at the damage inherent in associating with a Patterson, Mike hides himself away from the realization that he did that to her.