OP, please stop feeling guilty about everything that will negatively impact HIM!
You said that he wasn't a particularly devoted father, or husband. You clearly weren't staying for financial reasons!
You were in a marriage for love, and you're not in love anymore.
You don't owe him an easy privileged lifestyle. Your skills, dedication and hard work earned him that. When the marriage was happy. Not indefinitely.
He didn't earn it.
He didn't make sacrifices personally to facilitate it, unless there are massive omissions.
It's quite probable that he engineered the unemployment to try to gain sympathy- and a lot of your money. Including money that you have yet to earn!
Instead of pitying him for losing his privileges, start pitying him for being unimaginative and pathetic.
It's not that he's incapable of supporting himself. He's just used to having you do it.
Protect your children. You will be responsible for supporting them, facilitating education, holidays, lifestyle.
Please don't consider compromising their childhood experiences for a grown man who has abdicated responsibility.
If a woman was posting from the other side, everyone would be telling her to get a job, and stop being grabby.
He's perfectly capable of managing comfortably on 45k. He just doesn't want to.