Better to discuss it openly with your fiance, since you'll have to rely on him to take care of you when you're sick. I don't talk about my problem all of the time with mine, may not even say the "D" word frequently, But he knows when I say "I'm feeling bad," what I mean. He's good about not making foods too spicy because he knows that can bother me. And omlets. For some reason an omlet will do me in. I can eat all of the ingredients separately or even all together in a mix that we call "breafast skillet," but for some reason the omlet formation itself kills me. Weird. But he knows not to fix me one. And I know if I got sick at a restaurant and told him I needed to leave right then and there, he'd pick up and do it. He's even stopped the car and made me go to the bathroom although I told him I could wait we got a little futher down the road.
He happens to have a bad back and bad knees (and right now something's wrong with his left shoulder), so I have to take care of him too. He knows he can tell me "I can't do that" or "I need to lay down for a bit" and I'll put whatever we're doing on hold, do something else, etc. Should have seen us at Mammoth Cave trying to find a tour that wasn't too long--since I was popping Immodiums because of my daily diarrhea--and one without too many stairs. Luckily my Immodiums held and I didn't have to roll him back up to the visitor's center, lol.
They say you always should discuss finances, debt and personal spending habits and get a financial game plan in place before you walk down the aisle; I would add to that physical ailments and reoccuring health problems. Not because it will come as some big shock after marriage and make things rocky, but just because you need to support each other.