The only reason I could think of, "for you not having the right to wear women's clothes" would be the fact that none of use CDers have ever had a period. Or it could be that she views the wearring of dresses as a way of tempting a man into her feminine web, so to speak, and she might be afraid that you are wanting to trap a man for yourself.
I am sorry the two of you had such a blowup and I hope you work things out, Goood Luck.