I am a crossdresser who lives with my girlfriend. She also has a 21 year old daughter who keeps her clothes at her house, but stays elsewhere. She is in and out a few times a week.
My girlfriend knows I crossdress and supports and encourages me. Each night, I wear a half slip and panties to bed. This is also part of our intimate life. I have only one half slip, a black one. Once, when it was in the laundry, she said she would check to see if her daughter had one I could wear. I said "never mind," and just slept in a bra and panties.
Well, about a month ago, when nobody was home, I was curious. I went into her daughter's room and looked for some slips

. I found 4, 2 white and 2 black. One of the black one's was just like the one I owned with lace trim on the hem. HOWEVER, there were a couple of differences. It is tighter (small vs. medium, and shorter, 4 inches above the knee vs. just below the knee.
As I did love this slip, I put it in my drawer with my other one and have been wearing it to bed ever since. Her daughter NEVER wears slips anymore (it has been over 3 years), because she is just not that type. I, however, am feeling very guilty and have two questions. First, do you think my girlfriend has noticed the differences in the slips and is just being quiet about the whole thing? Second, should I tell her what I did, and accept any punishment?
Thanks so much for your advice,