I think you could reassure your spouse a bit by taking a gun-owner’s safety course. They are given by, surprise, the NRA and other groups, but they will show you how you can childproof and criminal-proof your gun. It is easy for a criminal to use your gun against you, and so increases the danger to your family, whereas your intent is to reduce it.
Take the course together, and let her see it is possible to be a responsible gun owner, and help her to assuage her fears.
Do you know what her fears are?