Does having a serious health problem mean I can't have a normal relationship?

I have suffered from GI/"gut" problems for over 25 years now. I've learned--mostly through trial and error--how to manage it with diet and supplements...well, mostly manage it. I'm not 100% free of issues now, but I've eliminated most of them. The trouble is, I've been through two dysfunctional marriages and now I'm unhappy in my current relationship. And I've recently begun to wonder if maybe I just need to accept that I can't have a normal relationship due to my health issues. I and the woman with whom I'm with get along fairly well, but we've become like roommates and friends. She lost much of her sex drive and I have lost my attraction for her. I chose to leave/separate from her once but came back after I started grad school (and she seemed to have changed, but the changes I saw only lasted a short time, then some troubling things reverted back to the way they were before). It was difficult for me to categorize this issue, because I feel it's a relationship issue, but when it comes right down to it, it's primarily about sex (or the lack of it in our relationship). There's no passion, and I feel like I need that somehow. And, yet, I wonder, do some people--people with a time & energy-consuming health problem like me--just learn to live without it?

And how many years ago was the start of that first dysfunctional relationship?