I understand that completely Mic, things are fairly similar between me and my wife.
We met through our mutual love of Doctor Who on Facebook. Didn't actually meet in person the first time though for over a year. It was another year almost before we met again, and again, and again...
Eventually we fell head over heels. I was honest and upfront about my illnesses, as Lucy was about hers. Although hers took a huge turn for the worse only a month after we officially started dating when she was diagnosed with terminal cancer. I proposed at her bedside the same day, after getting permission from her dad, and she thankfully accepted.
We were married two months later at a registry office (neither of us are big church believers) in a Doctor Who themed wedding.
Lucy is still with us, and I love her more and more each day. I look after her on her bad days, and she looks after me on mine. You could say it's a mutually beneficial arrangement!
I know one day things will take a permanent turn for the worse with Lucy, so I cherish the good days we have now.
Like you, I cherish our commitment and til death do us part really does mean just that with us.