[MENTION=104946]b dub[/MENTION], I'm sure your wife is a wonderful lady and that you two have a beautiful relationship. I say if she want a kickstand, get her one. Anything that makes someone want to ride their bicycle more often is a good thing, in my book. You know the potential frame damage dangers, so you can take the available precautions. First of all, does the bike have a kickstand plate? A lot of mixtes and other step-through frames do. Whether it does or doesn't affects your choices.

I would go for a two-legged kickstand if I were you. It's more stable and therefore more useful. Also, it eliminates the danger of the bike falling over with the stand out and twisting around the frame.

Copenhagen Dual Leg Kickstand - Chainguards, Frame Protectors, Kickstands - Accessories