Another vote for the Glock 19.
Small enough to conceal well, big enough to serve as a duty weapon, plenty of capacity for its size, lightweight, tough, reliable, and accurate. The proven design is backed by a tremendous aftermarket of accessories. G17/18 magazines can be used when more capacity is needed/wanted. Tennifer finish is very corrosion resistent. The Glock is easy to field strip and clean. It is also easy to detail strip for repair, installation of upgrades, and detail clean.
The fact that both you and your wife use the same system is an advantage. Your pistols, mags, parts, and ammo is interchangeable.
The 9mm cartridge in itself is an advantage. It is cheaper to buy, allowing more training with rounds downrange. More training leads to higher proficieny. The 9mm cartridge is also extremely popular. Where ever ammunition is sold, you will find 9mm, if in stock. Defensive ammo of today has been proven to be effective against live threats. There are many different weights and styles to choose from. While it may not be the most effective defense caliber, it is still effective. Shot placement is king, not caliber.
Should you get into reloading, 9mm is very easy to reload. Wealths of 9mm load data can easily be found online as well as in every current load manual that covers pistol calibers. You can easily cut your ammo costs in half by reloading, I did.
I think you made a good decision. The Ruger SR9 looks like it is a good pistol, only time will tell. The recall turned me off of them. It doesn't look like it is going to fade away, so if you decide that you want one in the future, there should be plenty available.
Good Luck