S.T.
i'm glad you're taking the time to think this over carefully, and thank you for giving a succinct overview of the mitigating factors in your question.
this is an even more precarious situation because your marriage sounds as if it's not a source of joy, support and appreciation at all, and that's the looming issue that overshadows all the others.
under most circumstances i'd encourage you to take the promotion. not just because of the money, but because of the positive energy created by traveling an upward trajectory in your professional life. and having that additional security would, i think, be helpful in evaluating a crisis that i foresee coming toward you in the near future, and that's what to do about a husband who doesn't contribute to the household and tears you down.
i'm so, so glad that you're not seriously considering another baby with him right now. despite your issues with depression and anxiety, and the pressure he's putting on you, you're keeping a clear head. i so admire you for that. it can't be easy to do.
so while i want you to be making more money and becoming more financially independent which will give you more choices going forward, i can certainly also see how it would create other and even greater problems, namely that you'd have less time to take care of the household in which you're getting zero help, and mostly that you'd have less time with your son.
is it possible to have a conversation with your supervisor about taking on some additional responsibilities, even if it doesn't result in more pay, but being firm about not spending any more time actually working? that is, keep boundaries around your time, but demonstrate flexibility and eagerness to move up within those time boundaries. while it would result in more stress and responsibility at work, it would also keep the professional door open while you work out the home issues.
and i think that's where you need to laser focus your attention. no one should be walking on eggshells in their home, their sanctuary, their sacred space. you need to get into marital counseling to work out better communications skills with your husband and/or personal counseling so that you value yourself more highly than settling for a lifetime of this.
and you know what the crowning concern is, right? that your son is internalizing all of this as 'how relationships work.' and you sound way too smart to want that to be a thing.
you have difficult decisions to make, my dear, and i don't envy you, but i'm so rooting for you. keep that wise head on straight, and untangle this strand by strand so that you and your child end up strong, confident and happy.
ETA after reading the other responses, i have to concur. if you take the promotion you'll have more money to hire help, and that would take a lot of your stress away. but mostly it will empower you to either redefine the parameters of your marriage or make it possible for you to start over as a single mom. either would be an improvement. good luck!
khairete
S.