I'm a domestic relations attorney, and while I'm a young one, my observation is that the number one thing that leads to a person calling me about a divorce/dissolution is a lack of communication. This in turn leads to each spouse making negative assumptions about the other spouse, which in turn leads to a failure of trust, which in turn leads things to compounding and spiraling out of control until their negative assumptions prove unsolvable, upon which time they pick up the phone and call me.
OP, I don't walk in your shoes and I don't live your life, but your post just seems to have a lot of these types of assumptions.
My husband now wants to work another ten/twenty years (basically till in-laws are alive) to provide for them.
I certainly think a discussion needs to be had about how much money he is sending to his family, but with that said, are you sure this is the sole reason he wants to keep working? Sure, he might be flowing a lot of money towards his family, but is that alone proof that it's the sole reason he wants to continue working? I know plenty of people with FU money who continue to work in very high stress jobs because they either enjoy the job itself or the sense of purpose it provides.
I tried a year sabbatical and it ended up I was doing all the chores at home while he went to work and relaxed. I just ended up being a glorified maid. So I don't think me FIREing alone would help.
He went to work and relaxed? I thought you said his job is "high stress"? Maybe you mean he went to work and then came home and relaxed, but in that case, I think that's a fair trade in a relationship. I work about 45-55 hours a week, and my wife works 25-30 hours a week. She does all the grocery shopping, laundry, dishes, etc. I still put my own clothes away, put the dishes away, do all the yard work, etc. (what a hero I am), but when one spouse works less than the other, doing more chores around the house only seems fair to me.
He is a great person otherwise (even though we have some differences of opinion) and a good dad but working for ten/twenty more years to fund someone else's lifestyle is making me sick. Our work is high stress and I worry about our health and the toll the jobs take on our family. I don't want to die early and leave my kids alone. My husband says family will take care of them because that is what families do. Even if that's true, I want to see my kids grow up, see them get married and have kids. I'm wondering if it would be better if we separate (we'd still end up with enough for both to FIRE separately).
As the son of divorced parents, I would encourage you to do anything and everything to resolve this issue prior to filing for a divorce/dissolution. It will absolutely not be better for your kids if you separate. It will be a PERMANENT pain in the ass for your kids. I'm 30 and still get annoyed scheduling things around the holidays.
But here's the biggest issue I see: you yourself took a sabbatical, and all that led to was you feeling like a "glorified maid" (as you put it).
Is it possible that your husband observed you and your emotions during your brief FIRE (which is what it was), saw that you were unhappy, and wants no part of that himself?One of the most underappreciated aspects of FIRE is, well, what the hell are you going to do with your time? I personally struggle with this mightily. I'll probably work out, take long walks, read books, fix some things around the house, volunteer at my local park, coach some sports...and then what? I'll still have a ton more time. I've ultimately decided that I'll probably continue practicing as an attorney to keep myself sharp and busy.
It sounds like you don't know what you want with FIRE yet, and that's an internal issue. But no doubt, this financial issue with your husband is something you really need to work on. Whether this comes through counseling or a frank discussion, I'm not sure, but I encourage you to really start afresh with him. Others with more lengthy marriages will have better insight than I do, but maybe propose the following:
(1) He maxes 401k every year;
(2) He maxes child college savings every year;
(3) He maxes all tax-advantaged accounts every year;
(4) He brings enough take home pay to cover monthly expenses (which allows your nest egg to balloon); and
(5) The remainder can be up to his discretion.
You could obviously tweak this, but this concretely forces him to put your family first, which seems to be your biggest priority (and rightfully so).
As you indicated, he's otherwise a good spouse, person, and dad. Those don't fall off trees, so I hope you can work out both your marital issues and your FIRE goals.