I'm a fan of 9mm revolvers and have had several, the one that I've kept is a custom S&W 360J that I had worked over and rechambered to 9x23 by Pinnacle. For me, a 13oz 9mm snubby is the perfect BUG/pocket gun, for my wife, not so much. The recoil is similar to +P .38spls in a light revolver, to much for her at her level of experience. Out of all the guns she's tried out the one that she chose is a S&W 317 8 shot .22lr revolver. It only weighs 10oz and, of course, even at that light weight there's no recoil. Would I like her to carry something in a larger caliber? Sure I would, but this is a gun that she chose, she shoots it well, she likes to practice with it, and she'll actually carry it, which is the most important thing.
Like most things in married life, what you think is right for your wife and what she thinks is right for her are usually two vastly different things. Let her try stuff out and decide for herself.
BTW, I agree with Weblance, and LCR in .22mag could work, S&W also makes the 351 in .22mag (it's a 7 shot). I'd be willing to carry either in a pinch.