While I don't personally know you, I feel like you are getting the fairly standard "SO treatment", as I call it. My ex did the same thing to me while we were together. I think sometimes SOs just are always going to be that way.
The other day when I dropped our son off to her, I asked her, as nice and sweet as I could, to "Please stop using male pronouns on me". See, I have custody of our son, and he calls me Mommy now also. We call her "Mommy number 1".I understand that she could have feelings that I'm trying to take her status from her, or trying to disavow my fatherhood, but she refuses to even talk about it at all with me. She said "You're a man, and you always will be".
I've been on my own with our son since he was 3, he's now turning 8 in a couple weeks. She disappears for months at a time, never has him on the weekends when she's supposed to, and makes no effort to call him on a regular basis, so yes, even before coming out I have been his mother and father. I don't even say things like this to her, because while I don't love her, my son does, flaws in all, and I would never hurt something my son holds dear.
This is relevant, I swear! My point is that what is the definition of a woman? To my ex, I have to be able to bear a child, I suppose. But there are reasons why cis-women cannot have babies also, are they any less of a woman because of it? I think that she knows I'm a woman, but due to pride,she'll never admit it, and I think she takes some pleasure on telling me "you're not a woman", because she knows it hurts me.