You are married to an addict, and it's imposible to be happy living with an addict.
He's addicted to work. Work will always come first. It's more important than you, his children, his wider family, friends, even his own health. Work is his god.
And worse, he thinks that you should give up being a person in your won right, and exist to be his support person. Doing everything else in his life for him, picking up the slack, doing 100% of the parenting, 100% of the housework, 100% of the life admin, 100% of everything else. And he doesn't think you should EVER ask for support from him. He won't give it if you do. Because, to him, no support you need is more important than the god of Work.
You have had health problems that have been a barrier to working. You've had to do all the parenting and life management, which has been a barrier to working. He seems to think the childcare bill is all yours if you work (absolutely no logic in that at all).
So, while he's immersed himself in work, your earning potential (and pension potential) has diminshed, meaning you're financially disadvantaged by his decision to make earning money his one aim in life.
Then there's financial abuse - you've made HUGE sacrifices so he can work, yet you don't see the beenfit of the money earned. He no doubt thinks it's his money because he 'earned it' (forgetting that he couldn't earn it if you weren't there enabling his life).
You definitely need to leave him. For your own sake but moreso your children, who are being impacted by having a disinterested dad who they have to live with but without him being present. They may go on to meet someone like him and think that's normal and so end up marrying them, or they may turn into him. Either way, it's not healthy. And there's time to change that outcome. And for you = your life will be so much easier, and happier, and calmer, away from him.
I'd suggest going to see a solicitor. Don't tell your DH you're doing it. You can keep this to yourself until you're competely ready to tell him, and only do that when you've got a clear plan and gathered together as much information as you can. See where you will stand legally and financially. You will feel better with every step you take. When I left my ex, I spoke to a solicitor then just sat with the inforamtion for a few months. One day I knew it was time to tell him, and in the meantime I'd had time to work through scenarios and to have a clear plan in mind.
You can do this.