I'm interested in this. It does impact what may be happening and how things could develop.
You're certainly describing a person who is more narcissistic than average - what, in common parlance, we might call "full of himself" or self-absorbed, maybe self-important. Personality characteristics exist on a sliding scale, and having zero narcissism is just as much a disorder as having too much.
People with personality disorders are what we used to call "mad" (a useful word, now sadly disapproved!) Their responses to situations can be abnormal and, most significantly, are inflexible. Even when their abnormal behaviours cause serious problems they could do without, their thought patterns are too rigid to change. They can manage a slight tweak here and there, yet it makes no difference because they operate to psychological scripts from which they cannot deviate. That's the element making it a disorder.
The only exception is psychopathy: people with this disorder can adapt and incorporate other people's perspectives into their scripts. People with the other disorders do not actually believe or care that different humans think & feel differently from one another. Psychopaths, by the way, are very narcissistic.
Would you say your mysterious husband is "mad" or just a bit in love with himself? How does he react to criticism, perceived slights or not getting his own way? Has it ever seemed a bit over the top to you?
Why isn't he working at present? Sorry if I missed it - is it some outside cause like an injury, or does it have anything to do with other people stitching him up, letting him down and generally failing to revere his unique brilliance?
Would you say he understands other people? In his relations with you, children, family or friends, does he seem to have a single, rigid picture of who they are or does he demonstrate insight into their individual lives and characters? If the latter, does this seem within the range of normal engagement or is there an element of manipulation, looking for the hooks or weaknesses that could be employed to gain control?
Does he despise a lot of people? I don't know about you, but most of us despise a lot of people! Most of us wish no harm to them, though, and would rush to their aid if they needed it. Disordered people wouldn't unless there was some benefit to them.
Finally, does he have unusually high or low expectations of your children?
You obviously don't have to answer any of this - and I am not performing an internet diagnosis. It's more that I've picked up a few things you've said and am concerned about the effects of a potential absence of normal morals/ethics as you proceed with trying to solve the problem in your marriage.