Don't get me wrong, I love guns. I love ammo. I especially love the combination of the two along with training. But the best answer to the immediate problem of needing a deterrent to someone kicking in your door WHETHER ANYONE IS AT HOME OR NOT is this:
A dog will bark at the door any time someone knocks, and usually requires no training to do so.
A dog will usually attempt to protect his "pack" AKA family/owners and, again, usually requires no training to do so.
I gave Moses a Kimber, but dogs don't really need guns considering they don't have thumbs or index fingers.
Beside being pets and family members, my three dogs are deterrents to anyone breaking into my home and stealing my guns or harming an un-armed family member when I'm not there to protect them.
Dogs. An awesome creation of God that bonds to and protects man like no other of the millions of species of animals on this planet. Crazy, ain't it? Until and unless your better half gets training and a suitable firearm, get a good dog from one of your local rescue organizations and sleep with peace of mind. Even a little chap who can't do much more than bark will run off all but the most determined of home invaders.