He doesn’t tell his wife because he’s probably thinking “Loose Lips sink ships” If his wife tells just one person about their stash then everyone knows when SHTF comes. Friends, relatives,strangers, etc.
I assumed the same thing. And then I thought " If he should have an accident and die just before the SHTF, I wonder if the wife knows where the SHTF food storage is located, how to unlock it (if necessary), etc."
If she doesn't, that would turn out to be one of those Twilight Zone (weird twist) situations wouldn't it?