Just leave him OP.
He's living the single life pretty much most of the time. He off about living it up going to his clubs and his sports.
He's swanning off totally reliant on your really hard graft as a mother and as a housekeeper. I bet he hasn't organised a damn thing for those kids during their lifetimes. He's leaving you to do all the donkey work while he has it easy, but gets to play the mature family man which we know pays off in the workplace in the eyes of others.
You are supporting him financially by doing so much. If you split he would have to make massive to changes to his life to have those kids fifty fifty. Which he should as they are half his. Plus you should push for that split so that you can also get your paid work back on track when you are better.
He's benefiting HUGELY from your unpaid labour and he's doing that while you are sick. Think of the costs he would incur if you split, he'd have to house those children, provide wrap around care, cook for them, clean for them, arrange for them. All of that would take a toll on his important man job, maybe that extra constant unrelenting pressure would fuck with his future earning potential too.
On top of this he is financially abusing you by not allowing you full access to money that is legally yours.
He doesn't even like you enough to spend his time with you when he's not away. They boyz chucking a ball about takes priority.
Nobody who loves their partner treats them like this, especially not when they are ill. He's a selfish manchild who wouldn't know real responsibility if it smacked him in the balls.
He just sees you (like so many misogynists on this thread) as both a convenience so he does not have to do the hard yards of family life but equally he diminishes and resents your contribution.
Your unpaid labour is equally as important as his paid labour, don't forget that.