Cat, I think counselling is never a waste of time.
It sounds as though your H is depressed, and it is a pattern of male depression that they externalise rather than face the stuff within themselves. So, he takes true (that is what is so awful about this) issues about you / the marriage and pins all his unhappiness on those.
(the reality being that there is no such thing as a perfect person/perfect marriage and true intimacy is to accept and love a person flaws and all, and work within that context to sort things out, with respect, humour etc).
One of the dangerous urges depressed men have, is to FLEE. So somewhere 'out there' away from you is where happiness lies. And they normally start vocalising their crazy when 'she' is in place.
I think you should look hard for OW. Know that there is only one person you can look after right now, and that is you. Living with a depressed person is, literally, hell, and I have found out they need firm boundaries. A grown man having a toddler's temper tantrum is dangerous to a family, because of the [economic and other] power they wield.