Hi Dorey, oftentimes we are alone with this. It is just part of the package a great deal of the time.
In one way I don't blame people like your husband, or my recently-become-ex partner for their lack of understanding or empathy. They have no way of really knowing what it is like, and it's not as if it shows on the outside. Plus, often they did not get together with a person who had these problems; they developed later.
This is not the case with my ex -- I gave a lot of information before we even got together. I warned that there would be times I would have to cancel plans, and so on, and that person agreed to be there for me but that turned out to be false. Of course, no one can know what it will be like to be with someone with chronic pain until it happens.
I know that if I were in their shoes I would at least be sympathetic and not so selfish as never to ask or care how the other person feels. But would I stay forever with someone who couldn't do the things I want or need to do, if I were the healthy person? Really, I don't know. I cannot say for sure I would, unless I were in that position, so my point is that just as they don't understand our position, we also don't understand theirs. I am not making excuses for their bad treatment of us, just saying.
What I do know is that speaking for myself, I am much better off in every way without that person who disbelieved me, made me feel bad about myself, and gave me a hard time every time I had to cancel plans. That only made my condition much worse due to the stress it caused me, and I am happier, healthier, and actually have less pain without that stress in my life. Having Fibro is very tough already. Better to be without a partner than to be with someone who makes it worse.