What reasons have you given her to carry? My wife seems to fluctuate a lot in her attitude toward my carrying. At times she acts like she doesn't understand why I do, but will often ask me, when leaving for work, "got your gun?" (along with anything else she thinks I'm likely to forget -- cell phone, wallet, and so forth).
I defend my carrying to her like this:
"I carry for the same reason I wear a seat belt, and have life insurance. I hope to God I will never need a seat belt to save my life, but if it ever comes to it, I'll be glad I wore it. I don't have life insurance because I hope, or expect, to die; but if I do, I would hate not to have it for my survivors. I don't expect to ever have to use my gun, and probably never will; but if I ever do need it, I'll be glad I have it, and hope God will carry me through on the basis of my having been prudent enough to be prepared."
There are other reasons, that make some sense to me, but are not as persuasive to others because they involve principles and presuppositions that others may not share. But what wife would not get the seat belt analogy?