I'm sorry to hear that things didn't go well. I'm sure things were horrible just as you left and I hope too many cross things weren't said.
As I said Upthread, I've had that sort of thing with DH so I might be projecting a little. The one who let me be the punchbag for his parents to use, as it spared him, from a lifetime of being their scapegoat child. Who wouldn't want time off from that? But it did damage our relationship (obviously) for a long time. Unlike others I know how otherwise sensible and lovely men can turn into something weak when confronted by domineering and abusive parents it's still abuse even if it's only that the child ends up in FOG. The parent neglected to allow their child emotional growth to become an adult - and bullies them if they try
It's funny how some people are commenting on how unattractive the OP's DH must be. WHY? Because he's supposed to be a big strong man? Give over the gender crap. He's a victim of his parents, same as a woman would be. He probably doesn't say 'no' because he can't unless he's a twat, in which case she's just married to a twat because he's in a learned panic driven position. You want him to override years of his mother's manipulation in one thread?
It's taken me over a decade to get my husband to admit that his parents are the problem; not me, not him. And when he even gently stands up to them they go on the attack and get nasty very quickly.
Of course he might just be a twat, but chances are from the descriptions of the MIL that we're talking of someone with no boundaries who only thinks of herself. He grew up with that.
He's probably a nice guy, probably even a people-pleaser. It's not about cutting apron strings, it's about building the persons self-belief up from where it was stamped into the ground at every opportunity to the point where they believe they deserve better.
But the OP needs to put her boundaries down for her own sake, and I hope that's what you've done. I hope this is a wake -up call for him that you and your children are his priority, not his mother.