OP here. Thanks all, this is about what I expected.
ExDH makes 3-4x what I do and will have an inheritance of 2-3M, but he's made a point of 'punishing' me for divorcing him and, yes, he would extend it to the kids. So I can't count on it.
I'm thinking of earmarking an additional 50-100k per child from retirement, working longer, and holding off on any big vacations for 3-5 years. I actually love my job and expect to work longer, just being conservative. My field also tops out at 100k annually, so that's my max income.
It's just been a long and tough road to get here, but I need to just dig deeper for the next five years.