OP, I do think some of your backstory is relevant..... (and I've followed your thread since the start)
It appeared as though you were a SAHM for 5 years while your dh supported you; it sounded as though you were neither willing to work nor study, when in fact you ARE studying (yes?) and you have at times at lest made an attempt to hold down a part-time job. And presumably before you were with dh, you managed to support yourself and your ds?
That all makes a slightly different context. Are you studying something related to writing? Or at least something that will enable you to take a job that feels like less of a drudge? What is the timescale for completing your course? In terms of your future plans it makes a big difference whether you are doing a six month vocational training course which will enable you to get some more fulfilling (and possibly better paid) work, or if you are at the start of a six-year part-time degree.
However, I still think you have been given some excellent advice. And also some questions remain unanswered. You said you'd already had work published - were you paid for this, and do you know how much? (you don't have to tell us, but YOU need to know whether your writing can earn some income in the short term, and it will help you discuss the whole plan with your dh).
You have not responded to suggestions about sending the first 3 chapters of your book to a publisher / agent (which sounds like pretty sound advice from people with real experience) - do you intend to do this? It would give you a sense of how publishable your novel would be, and again it would give you some real facts for you and dh to have a discussion about.
Once your ds is settled at school, would it be possible for you to find some part-time work (even if it wasn't exciting or fulfilling) which would add to your life-experience, and which would at least bring some income. Are you willing to consider this?
But the bottom line is that you and your dh really need to sit down and agree what are the priorities for you, and for him, and for you all as a family. It sounds like your dh's dream is (not-unreasonably) to achieve for himself and his family - buy a nice house, enjoy holidays etc. And he is willing to work hard in order for this to happen. Your dream is to feel fulfilled as a full-time writer, and hopefully to earn through this. And between you, you are going to have to listen to each other, understand each other's dreams and priorities, and help each other to achieve that.
And then to agree, between you, a realistic plan to make that happen.
At the moment you're in a bit of a stalemate. You're not supporting his dream (of buying a house, having more money to fund a more comfortable lifestyle), and he's not willing to support your dream (of writing full time) which at the moment can only be achieved by him working hard to pay rent, bills etc, and not having much left over for his dreams.....