StarTrekAngel, I know exactly what your wife means. I'm like that with neckwear for some reason. I love them and how many women wear them and a little silk scarf can look so utterly feminine. But if I try to put one on, I feel as though I look like it doesn't belong to me. Despite people saying how great it looks and how much it suits me, I can't see it and I don't know why. I think its improving because people have bought me nice neckwear and I've had to wear it and although I feel really self conscious, a few compliments and I start to feel more comfortable.
So next time, perhaps buy your wife something that isn't wildly beyond her comfort zone and make sure the compliments flow when she wears it. Your confidence in how much it will suit her might help her to try something new if deep down she might like to.