Get what your wife wants. The firearms industry has a biased opinion. For home only use, a 4 " barrel .357 will shoot .38 with less recoil and you always have the option to use .357. Just make sure she practices with whatever you guys decide on.
I'll qualify my opinion with telling you that I don't own a revolver.(yet) I like the looks of the Ruger GP100 for home defense. It has a good reputation for being dependable, it holds 6 rounds, there are good aftermarket options like Hogue grips, and it looks like it has good sights. I can't tell you which pistol has the best trigger, but others will chime in.