Azure, this is nothing to do with being with a long term partner; and your DH's lack of empathy is assuredly not a 'man thing'. Lack of empathy can occur in men and women, and it makes for very disheartening relationships.
As you describe it, you're living with a pretty chilly, controlling individual. Not a loving, healthy man at all really. His being happy and bringing you a cup of tea in the morning does not mean your relationship is ok, or that he is ok.
You're talking about a relationship where one partner is deeply unhappy, and the other thinks everything's fine (note, he doesn't actually care that you're unhappy. Normal men care about the happiness of their partners. That's what love is. )
It's also a relationship where you're unable to discuss anything, since you fear the silent treatment if you argue. Silent treatment = controlling behaviour....and it seems to be working.
Also, your DH is a man who left you pregnant and close to death, yet instead of cleaving to your side as any loving man would, he runs away to teach Sunday school!
What was he teaching, the redeeming power of love? It's something you do, not talk about. (Sorry, that was me metaphorically ranting at your H, not at you.....But you see my point.)
Azure, this is quite a bit worse than you think. And it won't improve.Take some time to visit a solicitor and get some clarity on your financial position.
Try not to sorry about disrupting your children's lives too much. Chances are they are suffering too, even if they aren't showing it.