"Fetish" is defined as an interest that takes over from conventional sex. According to definition, if you have a fetish, you are sexually aroused by/interested in the object, be it latex undies, a shoe, or a diaper, not by/in the person who may be wearing said object.
I/we don't have any of those.
But assuming you mean "kink", not "fetish", well that is a different story.
Diapers have become our #1 kink, but we also like wetting, sex toys, spanking, bondage, mildly painful clamps on tender bits, anal play, lingerie, and provocative clothing in public. (On her. I don't think I'm provocative, ever.)
Her with her leather harness holding a dildo up her pussy, wearing sexy undies, with clamps on her nipples under a thin shirt in a restaurant? Yum!
Diapers and sex have led to a newish discovery: smell. She likes to go for a few days of having sex and being diapered a lot, it makes her aroma unbelievably sexy, to both of us. She likes the way I smell after being diapered for a while too. I've always loved her scent, but combining pee and pussy like that is a new level.
I'm sitting her ticking things off on my fingers - I think that is the lot!