I think you probably nailed it with the feed lips comment. It's probably bowing outward at the front of the lips, but you should also closely check the top/rear edge of the mag, where the feed lips meet the back edge/spine, and make sure there are no visible cracks. If so, it's time for a new mag, no matter the cost.
If you only have one mag, I'm VERY hesitant to suggest taking any action to "fix" the mag, as it could make it worse or damage it, leaving it completely unusable. Periodically check with Gun Parts Corp to see if they get any mags for it, and if they do, buy a couple. Magazines really are the heart of an autoloader; the best gun in the world is only as good as the mags used to feed it.
Have you had your wife hold a medium-frame (Cheetah-size) Beretta DA/SA .380 or .32 to check the size/feel? I forget the model number(s), but they have made them in single-column versions in the past, and they are relatively slim.