HI Sammie,
It could be your wife is holding out an olive branch of sorts but as others have said it is not good to try and guess the meaning of those comments. I would just take a moment, sit her down and discuss it exactly as you described it to us. Find out where she is with all this. The comments were made but you need to bring clarity to the meaning "filling in as a GF" may be just a quirky way of saying I don't have friends right now so let's do things together. Having the conversation now will help to establish the ground work for future communication. Just curious, you said she knows you have an interest in women's attire but does she know you dress?
Hugs
Isha
