You've been rejected by these three young people (sorry, I can't call them kids, even the 16-year-old), and you want to turn that around by bending to them. This has nothing to do with your identity, Rachel. You are who you are. If they rejected you because of your profession, would you change that? Because of your skin color? I'm sorry, but you can't control what other people think. You can only be yourself, as best you can, and let other people make their choices, however painful. Including this woman you love -- perhaps she recognizes, better than you, that her children are old enough to do what they need to do, and she needs to do what she needs to do. This is kind of how people discover who they are.
If you tried to be someone else, you would fail, because you can only be yourself.
As to matters of libido, I've found progesterone (bioidentical) can do wonders for that. Women have libidos that aren't driven by testosterone. You don't have to live as a post-menopausal woman. Something to talk about with your endoc. There is more to hormone therapy than physical development -- there are also matters of psychological well-being to take into consideration, too.
Finally, I'm curious about this averring that you don't have genital dysphoria, and yet you say you'd get SRS "tomorrow" if it weren't for this relationship?
But she's "very very supportive" so it's not like she's stopping you. Well, except for liking certain aspects of your maleness... I tell you, I was in a relationship during transition as well, albeit a pre-existing one, and yeah, she was very very supportive, and very very loving, but she was also very very sad about losing the kind of sex life that she wanted. And this wore on me. Because I needed a certain kind of sex life, too, and it had nothing to do with retaining anything down below. Or retaining any aspect of the previous role in life that I had pretended to fill. And when it came down to it, the most honest thing for both of was to go our own ways, because an authentic relationship can only be founded on being fully authentic people. If either of you are making sacrifices out of fear of loneliness, I'm sorry, you're not being your true selves.
I don't think the dream you harbored all your life, Rachel, was to live in a half-way state of androgyny.