I was diagnosed with fibromyalgia in my mid 20's (I'm early 50's now) and my then-partner felt as you do. And after a couple of years, he really resented me for being a "buzz kill." We eventually parted ways. It took years to find the right doctor to help me manage my chronic pain and fatigue. Subsequent partners were more understanding, which improved my stress (crucial to manage medical issues). I now have lots of tools (yoga and other non-medical exercises) to manage my symptoms. I live a super active life. My fiance and I travel a lot, are avid hikers, go to concerts, have a bunch of hobbies together, and just a good life. My ex from back then has told me how he regrets being so impatient. He wishes he'd handled things differently.

So, I would say, if you love and adore this person, have some patience while they seek medical care. Be a source of comfort. But it can take time. So I totally get it if this is too much for you. There's nothing worse than feeling like you are a burden. Life is short and we should all be happy.