Your wife just needs to be more careful about who she opens a door to. She doesn't have to be paranoid. When the UPS guy shows up in uniform, with a shiny new UPS truck parked outside, and the package you ordered from Brownell's she could answer it. If a guy shows up in a UPS uniform driving a Honda, and has an unexpected package... maybe not so much.
When in doubt, just don't answer the door. And if the situation is out of hand, call the police first, your husband second.
As for carrying at home. Not the big deal that some people make it out to be. I have a S&W J frame in my pocket from the time I wake up until the time I take a shower and go to bed. I move it, with my car keys and wallet, when I change pants. Some people arm themselves to go to the corner store or bank. I don't make all those "paranoid" moves, because I'm already armed.