Re: Having nothing to do with the pending ban
Some random thoughts for you.
Most, if not all, modern single or double action revolvers can be safely carried with the hammer on a loaded chamber. An internal safety feature blocks the firing pin from the hammer so even if the gun is dropped on the hammer the round will not be fired. The only way to deactivate the internal safety is to pull the trigger.
Your wife will not fire off four or five extra rounds due to a nervous finger if she has a double action revolver - the trigger pull is too long and hard to have this happen. And if you go the revolver route, make it a double action one.
There is a ton of debates over the merits of a revolver vs a semi-auto pistol. Choose what you and your wife are comfortable with, competent with, and confident with.
A 357 magnum has excellent stopping power but when fired from a small snub nosed revolver can have a very unpleasant recoil. Good grips and practice helps to control this. The mistake many make though is to shoot low powered 38 Special rounds instead of 357 ones. You will need to occasional fire the same type of rounds at practice that you load with for self defense. A good alternative to a 357 is a 38 Special that can shoot +P loads. A +P load is between the regular Special and 357 so it gives an edge to stopping power without all the recoil of the 357. One more note on the 357 - the muzzle blast can be impressive at night.
Cartridges like the 380 and 38 Special are considered at the low end of the scale for stopping power. You can even throw the 9 mm in there too. The selection of a self defense bullet is more critical with these rounds to ensure adequate stopping power. For example, the 9 mm is marginal to unsafe with a 115 gr round nose bullet but generates much more stopping power when loaded with a 124 grain hollow point bullet. Generally the larger rounds such as the 45, 40 S&W and 357 do better at ending a threat. However, people have been killed from one lowly 22 shot and have survived multiple hits with 45 rounds. The trick is to choose the largest caliber that you can handle. Also, the 357 Magnum is not the same as the 357 Sig. The Magnum is for revolvers, the Sig was developed for semi-autos to give them a round with the same power as the Magnum.
1911 type pistols have the best trigger pull which definitely helps with accuracy. They are a solid, robust design with over a century of use behind them. But they also tend to be a little larger, hold fewer rounds, and can get picky over magazines, feeding, ect. They do come in a variety of sizes so I'm sure you will find one to comfortably carry and a good gunsmith can do wonders to improve their reliability such as polishing the feedramp to eliminate feeding failures (FTF).
With any semi-auto, if you have multiple magazines, it is imperative to run a couple of hundred rounds through each magazine to ensure they will consistently work with the pistol. If you have problems with a magazine then get rid of it. A $30 - $40 magazine is nothing compared to the cost of you or your wife's life.
Many ranges will rent guns so this gives you the opportunity to try out as many as you like. You can also see about borrowing different types from family and friends.