OP, this man was not even willing to put you on his mortgage. Why not? You are the mother of his children fgs! Does he not want that security for his own children at least? What is wrong with him? How have you lived like this all these years???
Whose line is the "We don't need to be married as it's not the Victorian era?" Let me guess...
So basically, he's been perfectly happy for you to get up at 2.30am (!!!) for years in order to work around the kids and do everything else so that he didn't have to. This has massively benefitted him. Look, he has children - but also a home, presumably a pension and he has sailed on through the years, working full time. No housework, kids issues to factor in because you have facilitated all that.
You also have kids. However, no career progression, no home, no pension, no savings.
Diabolical! OP, why did you do all this for a man who won't share finances either you or give you the security of a joint share in your home. This is the very minimum you should expect! Why even have children with a man who won't give you - the mother of his children - that security?
He has taken advantage of your best years so that he could progress in his career, pay of his mortgage etc while you take on the unpaid labour of HIS children and HIS house. What a surprise - now the kids are more independent he wants his money out if you in other ways - ie. 'You've done the hard bit with my kids - thanks for that, now get yourself out to work.' Unbelievable!
And no, he won't adjust his behaviour to take on any more housework or commitments to the kids. He takes all this for granted because he has been facilitated by you for almost 2 decades.
You need to insist he puts you on the mortgage. This is beyond ridiculous. Insist on joint finances. Insist he takes on more outside of his job if you return to work full time. Don't settle for any less. I say this as someone who doesn't work at all (SAHM with teens) but I'm financially protected and my husband wouldn't have it any other way (nor would I).