My ex. We were pretty well into the relationship, but in the first year, I told him that I identified as male. I was fairly unconventional when he met me, and I was casting off the whole girl charade, getting my hair cut, and buying men's clothing. So he was attracted to all of that, apparently.
Right before I met my ex, I was in another relationship when I read a book about FTM transsexuals. I don't know what my partners thought of it or whether they knew; I was probably dropping hints, but I really don't remember. Then again, I came out of the closet and went back in so quickly that I might not have given them any hints at all.