I may be thinking of the wrong poster, but aren't you and your wife very active/health conscious?
If so, I would suggest buying silicone wedding bands to use for the actual ceremony. They're very inexpensive, so even if just used for that it would be okay. But they would also be nice to have in case you're doing something active or travelling and want to not wear your expensive rings.
I know that would not be what most people would consider romantic, but I'm super practical and also not really a jewelry person (which you mention your wife isn't either) so I would much prefer something like this than my husband surprising me with something that I'm not going to use. Besides the practical aspect, to me, it would be more romantic for there to be some kind of significance (your hobby of exercising together) rather than buying a traditional band just because "that's what everyone does".
If you are really set on buying a piece of jewelry this is what I would do as well. A necklace that represents your family that she can wear on occasion.
If so, I would suggest buying silicone wedding bands to use for the actual ceremony. They're very inexpensive, so even if just used for that it would be okay. But they would also be nice to have in case you're doing something active or travelling and want to not wear your expensive rings.
I know that would not be what most people would consider romantic, but I'm super practical and also not really a jewelry person (which you mention your wife isn't either) so I would much prefer something like this than my husband surprising me with something that I'm not going to use. Besides the practical aspect, to me, it would be more romantic for there to be some kind of significance (your hobby of exercising together) rather than buying a traditional band just because "that's what everyone does".
I would get her something that represents your family, maybe something that has all your birthstones (like a necklace or bracelet) or a stacking set.
If you are really set on buying a piece of jewelry this is what I would do as well. A necklace that represents your family that she can wear on occasion.
)) and I wear them a few times a week. I love them and they are one of my favorite gifts from him. I don't wear necklaces or bracelets, so those would be a no-go for me. I also don't like the look of Mother's jewelry, but your wife might.

Seriously though, I'm pretty confident. As I said, this is very informal. Really more symbolic than anything. It's going to last all of a few minutes and be just the 5 of us.