As others have said, keepin' secrets from your wife never becomes a good thing unless it is a present for her. My wife, altho she grew up around guns and married me knowing well I was a gun enthusiast was uncomfortable at first with the loaded 1911 in the nightstand. She soon became familiar with it and realized it would not go off by itself. Now when something goes bump in the night or the dog barks suspiciously at something, she tells me to grab it and go downstairs and check. When CCW became legal in Wisconsin and I started to carry the J-Frame, she also was uncomfortable and asked, Do you really need to take that everywhere we go?". Wasn't but a few months and she began to not even notice whether I had it on me or not. When we go out to eat with friends and I drink pop instead of a mixed drink, when friends ask why, she is the one that tells them, "he's doin' it for your protection....." and says no more. Some know what's she's talkin' about, most don't.
You need to impress upon your wife that it is not just something you do for you. You need to show her how safe CCWing really is. You need to show her examples out in public where having a weapon on you is a good thing and being alone and unarmed is not. Do that well and correctly and odds are she will come around.