My wife does not like my XD9 or 92FS so we got her a LC9. She ended up hating it. She had the toughest time shooting it, loading the magazine and racking the slide. We took her to the range this last time and she was still having a tough time with it.
So.... I went inside to the shop and got a box of .380 for my Sig P238. She loved it, it was easier to load the magazine, easier to rack the slide, easier to take the safety off, easier to pull the trigger, easier to control and easier to do double taps.
She felt more comfortable with the Sig after one mag then she did with three range trips with the LC9. Much better shooting too.
I have ended up losing my P238 that I had for about two months after wanting one for three years.
She is not adverse to carrying it either..
Bottom line, if your wife is tiny like mine she will probably be more comfortable with something like the P238. I know you were thinking 9mm and a higher round count. But, if it is a choice of getting something she will carry OR getting a higher capacity 9mm I would choose the smaller one that she would actually carry.
I never thought I would get my wife to carry but now she is. Right now she is carrying with no round in the chamber and the safety on. I know it is not ideal but we are taking baby steps here...