Steelers, From what you have posted, it seems to me that your H is depressed. Like another person said, the alcohol is making it worse. He does sound paranoid. OW might be taking advantage of him now and fueling his paranoia and depression.
Don't make excuses for him, e.g. that he won't go to counselling or seek help because it's just not in him, etc. If he's so well-versed in psychology, then he has all the more reason to work on himself... He should know the benefit of working on himself. He has made the choice not to. And the alcohol is certainly clouding his mental clarity of his situation and of himself.
Pray hard and if possible, "act as if" he's behaving the way you want him to - to give him positive vibes for him to respond to. Thinking of you...
