Does this mean that you can dress, just as long as she knows about it? This seems reasonable to me. I would not like it if my SO preferred to keep this part of himself separate from our relationship. I would feel as if he was trying to hide something from me.
If, on the other hand, she does not want you to dress at all, you can reach down into yourself and tell her exactly why you need to do this, and what it does to you when you don't. You can also educate yourself about gender and gender non-conformity, so that you can answer her questions. You can ask her to tell you, specifically, what she doesn't like about the CDing. Has she seen a light in your eyes when you CD that she feels isn't there for her? Is she afraid that eventually the CDing will take over your life? Does she hold on to well-defined gender roles that she feels must not be crossed? Does she believe the CDing for you is a fetish? Is she afraid of the negative impact if others find out? Does she believe that it is morally wrong? Is she turned off with men who dress as women? Hopefully as you talk together, some of the misconceptions she may have will clear.
As to what made me, for one, accept what is outside the norm, there are several reasons: I've always thought outside the box and I do not believe in rigid gender and sexual roles. I came out of a traditional marriage with a man who did not respect basic boundaries and in contrast, my SO was a breath of fresh air. I do not believe that I have the power to mold others into someone they're not, in order to suit my agenda. I knew a couple whose husband is a CDer before I met my SO, and I knew their marriage worked. My SO told me at the very beginning so I didn't feel lied to.
