I've got Psoriatic Arthritis (and half the alphabet of comorbidities), thanks to my immune system's preferred methods of telling me it hates me.
I work - BUT - that's manageable due to finally being on the right medications, therapies and many years of adapting to the situation. And DP does more than I do at home because he doesn't have any physical difficulties.
I'm currently doing well and am actually able to gradually increase exercise, which although it doesn't 'cure' the autoimmune crap, it does make a huge difference to pain caused through deconditioning, reduces the cardiac risk, reduces injuries, etc - and makes me feel vaguely good about something my body does. If I could physically manage to get there, in the depths of a flare, it felt amazing to be in a swimming pool, but when I couldn't even manage that, I felt horrendous.
But then again, having work was also vital to start me on the path of increasing activity to build up enough strength to be able to consider the exercise - during my last flare, my daily steps would be around 26 if I didn't literally have to leave the house. When I first went back to work, they increased to around 2000 on average, but shortly afterwards, it was up to 5000, then 6000, then 7250 and so on. Because it gradually built up, I didn't have the crash and burn - and three weeks after that first exercise session, it was up to 8,450 when I'd thought I'd had a relatively quiet day.
I agree completely with him that the stress and strain of being the only earner is phenomenal, as I've done it. But I also agree that there's a possibility of increased pain when still trying to get a handle on disease activity; I certainly couldn't do what I do now ten years ago - or during my most recent/most severe flare, where I spent three months off sick and two of those barely able to hold a full mug of tea.
There's no right or wrong with this, tbh. Everybody's autoimmune disease is different in where it attacks, how it feels, how active it is right now, etc. The pressure that people feel from supporting a whole family on one wage is also very real.
It is unlikely that you will feel the way you do right now forever, though. It feels as this is it and it can only get worse - but that's the nature of autoimmune stuff, it tends to go from remission - relapse - remission or slow burns with occasional less intense flares - what it rarely does is stay still. I think it's good for my emotional health to remind myself even in the worst days that it isn't always like this - and perhaps looking for a sedentary, short hours job can help reinforce this for you as well as remind your DH that you aren't doing this for fun/pretending it's worse than it is.
After all, sometimes there is a choice of
Be exhausted and in pain whilst skint or
Be equally exhausted and in pain but not skint.
I prefer the latter.