A lot has been said, some of which I agree with and some not. Rather than quote everything, I'll pick out pieces and try not to distort too much --
Oh one other thing. Don't think for one minute that your daughters will see what you're doing and it will be a great example to them and they'll be proud of you and blah blah blah. Your daughters will see what you're doing, and whether they express it outwardly or not, they'll be hurt that you've chosen it over their birthday (oh yes you'll miss many), their soccer game, their ballet recital, and their need to cry on your shoulder over the boy who just broke up with them (you'll be on a 30 hour call and won't be available).
While this may be the case, I don't think it necessarily is. Yes, many children are so self-centered and short-sighted that they cannot see beyond their own self-interest. That's a childish outlook and they are, after all, children. But many other children
can and do see more. They can rise to the occasion, contribute more to the family's well-being themselves (cook, do dishes, get themselves off to school, etc.) and actually benefit from becoming more self-sufficient. These children can be inspired by their parents' continued growth and go on to become high achievers themselves because that is what they see.
I was a premed once too. I remember not understanding the full ramifications of going into this profession until I was in it. In med school I have seen people turn obese, have skin breakouts worse than teenagers, people needing to go to a psychiatrist for depression, people getting a divorce, I've read stories of residents committing suicide, etc. Yes, there are many/most people that make it out fine, but the journey is hard for everyone. My psychopathology here is thinking that family should come first before income and a job. OP has very viable alternatives for a better life that doesn't involve this kind of sacrifice. This would be very different if OP had a rock solid marriage with a husband that will pick up the slack. Maybe I'm reaching here and probably talking out of turn, but I seriously doubt this husband that's not the breadwinner will step up to the plate for his kids.
Some very good questions. If you were to choose a shorter but still intense career path -- say PA -- and the financial questions somehow were to be resolved to everyone's satisfaction. Would your husband step up to the plate and pick up the slack with the family? Would your kids?
I could absolutely be wrong here, but from what you've written, it doesn't sound to me like money is at the root of your husband's concerns. From what you've written, it sounds much more like it's about power, control, ambition and status, and that he would feel threatened by your success and increased independence however you were to arrange it. (Would your achieving more diminish him in his own eyes and in his perception of his children's' eyes?) If that's the case, then your options are to limit your own achievements and personal growth and thereby stay comfortably [for him] within the 'box' he's set out for you, or to strike out on your own (emotionally, not necessarily physically) and see if he can and is willing to adjust. Walking on eggshells trying to navigate all of his objections will be a losing battle because (it sure sounds like) as soon as one objection is overcome, another obstacle will pop up in another place. It's Whack-a-Mole with your dreams.
What would you do if he weren't there? Being a single mother is scary as he!! and it's nobody's first choice. But it is better than being in a marriage that's actively unhappy and diminishing. Has yours reached that point? A good, strong marriage is a wonderful thing and certainly something well-worth sacrificing for. But shortchanging your own future for a marriage that's not worth saving is not a good trade-off.
In any case, you don't have to make the BIG decision now. Take it one step at a time with the coursework, volunteering, shadowing and possible job changes you will need to further your various career options -- RN, PT, PA, MD/DO. At this early stage, they're all in the same direction. Get more specific when you have to and keep all your options open until then.
Best of luck to you --