I was married and had a similar experience. As I have stated before I have a long history of dressing up in my mothers clothes. When I was a young adult I moved in with my girlfriend and whenever the opportunity presented itself I would dress up in her clothes.
The first tome she caught me she got furious and began to belittle me and basically tried to end our relationship. Over a span of years she caught me wearing her clothes numerous times and eventually began to accuse me of cheating on her with men. Im not even attracted to men. She was a very insecure person and couldn’t understand that I can have issues with gender and still NOT be attracted to men. Anyway eventually we progressed in the bedroom to me fully dressing up but in the long run I believe it contributed to our break up. In the end she couldn’t handle or understand I’m still not very sure. She would encourage me to dress up but then she would put me down for it and tell other people that I would wear her clothes. Turned into a big mess. I guess what I’m trying to say is life is fragile and we should always tread softly and be very aware of who we trust. If you didn’t know you would never guess and eventually she felt betrayed that I didnt just tell her in the beginning but who does that.. either way good luck and IF she is truly understanding then count yourself as fortunate and be careful to not take her for granted