I do think it comes down to what indeed is mental health illness and what is adjusting to a nicer lifestyle. Many people make that choice from the start but this comes with much fewer luxuries.
I'm your case you met when you were clearly on that same level than him both working hard to afford nice things, supporting your children through Uni, nice holidays, maybe retiring earlier.
Then 3 years later you decide to give up work temporary. Your dh is supportive, you have the means to do it and he trusts that you'll be back at work earning good money again expect that only a year after marriage, you are now saying that you want an easier life whilst he has to support you and your children.
Of course marriage is for the better or worse, but you can appreciate how he could be thinking that you planned thus, even if unconsciously.
In essence you are saying that because you are married he should accept your lifestyle choices and becoming financially responsible for your children who has only been in his life 4 years whose own father doesn't pay for. Ultimately, they will use electricity, gas etc...and it will be him paying.
I think your OH is angry because he thinks you married him for the support he can be when your ex wasn't and yes, having the same life that he offered his ex which is what stressed him and he wanted out of. You were happy to be without a job for 18 months when you could afford it so he'll wonder what will stop you staying as you are if he starts supporting you, especially as the longer you are without a job, the harder it will be.
I think your plan sounds reasonable but why can't you take an easy pt job during that time? If you don't have a mortgage any longer, your monthly bills can't be too huge. If they are, can you cut down on them.
I think your oh will be more likely to help with paying some bills if you work and show you are trying to get back on your feet than he is to just give you money.
I know oh too well how you feel and yes, I would love my OH to say that I don't have to work or even support me to work pt because I'm struggling every day but I respect that it's not fair to expect my OH to take over my respibsibitues just because we are married.
I think you'll be fine. I expect the stress you've experienced and the fact you feel so much better in yourself now makes you very frightened to go back to work and it's thus fear that makes you angry with your oh. You'll get there, back on track, hopefully soon.