I guess I have been really blessed, my young bride of near fifty years has never said a word about my gun purchases, matter iof fact, she has purchased a large number for me. Both safes are buldging, and there are a number that have to be stored in a closet because the safe is full. When my wife was recently asked if she approved of me owning so many guns, and what did she plan to do with them if something happened to me, she answered, "that is a part of my retirement fund, if something happens to Bill, I will sell the guns and tour the world." I don't know how far she will get, but I do think she can take a nice trip.
If you convince the wife at an early stage that buying guns is an investment, that should make it easier. But in buying, try to buy quality, keep it in good shape, and it can truly be an investment.