I'd also recommend moving the thread over to revolvers and getting a 357, 4" barrel. 3" is better for concealed carry, but 4" is more versatile and while I normally carry the 3" I have carried the 4" a lot.
9mm might be cheaper where you live but with revolvers you can recycle *all* the brass... does your wife have issues with reloading equipment? :-)
My wife was also mostly anti (out of ignorance) when she met me, but she's a bright cookie and figured that guns are actually not an issue after observing me for the six months or so we knew one another but before she introduced me to the kids... yea, it was sort of facebook-it's-complicated for a while. So maybe you end up with one gun only, maybe it's the thin edge of the wedge -- don't push it, I find that vehemently anti-gun people are the first to scream "do you have your gun?" when things go pear shaped.
But if it turns out to be your only gun, a 357 revolver is IMO the best all-rounder.