The simplest way I have found to deal with this situation, opsec. No one knows, no one asks, no one thinks to head my way. The wife will occasionally talk about it with her bonehead family, but they all live across the country, so I don't worry much about them. Otherwise, we just don't talk to anyone about it. My boys grew up doing it, so to them it is just normal living, nothing to talk about.
When I get questioned about a big purchase, I just smile and tell my tale about have lots of kids and a wife who always loves more babies. Gotta make those dollars stretch when something is on sale. Or how much I enjoy frittering away a weekend canning with my wife cause I just enjoy spending time with her. Either one gets a big dopey "awwwe, dat's so sweet" and they chalk me up as a simpleton with misplaced ideals. Which works just fine for me.
Having a wife on board with prepping and having agreement on methods certainly makes life much easier. I cannot imagine having a wife who cares not about the future and lives only for the moment.
Then again, I would not have married such a woman to begin with.