Of course there are single mothers have a good income coming in. Very few of them have that from maintenance/life insurance.
They have it from working full time themselves. The overwhelming majority of single mothers do not get generous maintenance. They get a pittance or nothing.
I don't want you to become a single mother or poor. I just want you to have a realistic approach to your current situation.
If you try focusing on the good it might help you. The good is that your husband, despite being disabled and in significant pain, is still working and being the main breadwinner. Ok, he works from home now which you find challenging. He probably does too. But it is better than him not working at all, financially for your family and psychologically for him.
So look at the good and the real.
When I got very unwell and immobile for some time, I kept working. It made me feel human still when everything else was all over the place, and I felt useful to my family. I also worked from home. I found ways to be grateful - I had a job that I could do from home. My kids are healthy. I had good friends. I was 30 years old - and instead of focusing on how unfair it all was I managed to be positive.
You need to do the same. So instead of calling yourself a single parent when you aren't, be grateful that you aren't. Instead of feeling annoyed that it impacts you as well as him (and yes of course it does, but nowhere near as much) try having some gratitude that it isn't you actually going through the disability because believe me, that would be harder. Because at the end of the day, a big thing about disability is the removal of choice. You may choose to stay with your husband in which case yes, his disability will impact you fairly significantly. But if you wanted to, tomorrow you could walk away from his disability altogether. He can't.
Focus on the good and you might cope better. I'm sounding harsh I know but trust me. It's good advice. It was given to me and I took it. And then when the medication started working I was incredibly grateful and lucky but I was also in a mindset of positivity so the regular hospital visits, the giving up the sport I had loved for years and could never play again, the understanding that there would be certain things I would have to do a bit differently than planned with my children, places I will never visit because I can't have the vaccines etc - I could cope with.
Lots of people will "poor you" the situation but that isn't advice that will give you the strength to actually deal with it. I'm telling you, from experience, that the best thing you can do is to find the good. Yes moan to your friends a bit because its hard. But be realistic. Always end a moan with "but at least we....."
Stop claiming things that haven't happened to you, because it isn't true and it isnt good for your mental state. You need to be tough to get through this. I saw you said you won't be having a breakdown. Good. That is exactly the sort of talk that WILL get you through this. More of that will get you through.
I wish you all the best. Genuinely.