I feel for you

My ex was like this, never had any ill health in his life, and couldn't understand that I was in pain. He thought it was me being lazy, and making excuses for not doing things. I really wished he could experience what I was going through, to understand. As I said, he is now my EX husband!
I can't offer you any solutions to this (apart from divorce the b*stard!!!! (only joking!!!), just that you are not the only one who's partner/husband doesn't understand what you are going through. When you suffer from something like this, you will try anything to relieve the pain, and try to live a normal life.
I am lucky, my new partner (now fiancee!) is very understanding and supportive.
I really hope you two can work this out. Pain is not a psychological issue, it is a pain issue! Does he come with you to your doctors appointments? Maybe that would help him understand?
All the best,
Emma.