Ok, first, I see a lot of married people doing responses, and would be happy if you friended me, since we have both the marriage issues & diapers in common. Even those who've lost their wives, since you had the same experience. We really should have a group...
As for me, I told her about "things" when we we're still dating, and it went "ok". We had lots on our respective plates, so diapers seemed to be a kind if NOT-SO-BIG issue. Of course, marriage changes all, in one way, or another. For us, we wrestled with the "when", the "how", even the "why", and especially the " how much is too much". Add the fact that now that you have someone that knows, so you can delve a little further, exploring options (cloth vs. disposable, plastic pants, powders, creams, the whole lot), sometimes with their approval, sometimes not. Add 30 years of finances, home purchases & sales, cars, jobs, kids, family, holidays, and diapers upon diapers, and arguments & disagreements over all that crap. It's NOT EASY! Over time, you find a path that works. Sometimes you play together in them, sometimes not. Too much is definitely#2, the
... But, that's too much for me, too, so we're in agreement, and only genuine accidents are even remotely accepted.
It's definitely MY THING, but she does participate by making things, tolerating my choices, and trying to be involved. She has a full plate with grandkids, etc., so we just let life roll, for the most part. As others have mentioned, you can find your way through this, if there's love, mutual respect, & good communication. If there's not, this'll rip your relationship to shreds. You both play a part in its success or failure. It's not leaving any of our brains any time soon, so you might as well find something that works with someone you love, and allow it to find a buoyancy that's acceptable to both partners. It can be so awesome to merge it with another human, but it can also be a major cross to bear. YOU make the difference between success & failure!