Fabio, if I may chime in with my two cents......I would consider, if it were me, of going with either
A) .38 special revolver and .38 special rifle
Or....
B) .38 special revolver and 12 gauge pump shotgun.
Either way I believe the .38 in a 4" to 6" barrel wil offer the maximum stopping power with the minimal recoil and maintenance. You or your wife should be able to handle anything shy of hot +p+ with little felt recoil (assuming you can even find +p+ ammo or that your gun is safe to fire it)
The rifle will give you the advantage of little felt recoil, longer range and accuracy than the pistol and be a resonably reliable round for stopping man and beast. Disadvantage to snake killing unless you can find .38 special snake shot, which I have seen here in the us.
12 ga. Shotgun is good against ANY kind of critter, 2 legged or 4 although you or your wife may have a harder time with recoil. Get familiar with the different sized ammo (slug, 000, 00, bird shot etc...) By chooseing your ammo wisely you can set up for differnt threats at different ranges as well as have a fine weapon for hunting.
That narrows it down a little, hopefully you can convince the lovely wife to purchase a firearm of her own, 12 ga shotgun and rifle/handgun in .38 special would be optimal IMHO
Best of luck, I hope this helps a little.

-Bill Liptak