I think the duality comes in explaining it to others, because ultimately, the truth is simple: We are only who we are. Whether or not we are in the correct gender is still only a part of who we are. Because we can be nothing more than that. Duality outside of the mind does not exist. Just like life and death. These aren't two seperate things. As we are living, we are also dying. You cannot have one without the other, so it is only one. You cannot have one version of you without the other, so you are one.
We wouldn't seperate ourselves for who we are when we eat chocolate ice cream, and who we are when we eat vanilla. Yes, its a simple concept, but easily extrapolated into gender. if we transition, we still are only who we are...... just more of who we want to be.
For the longest time, I had thought "Who am I going to be when I'm a woman"? It had given me all sorts of headaches. The mind, anxiously dividing... searching in duality. Of course, the answer was simple, even though it took forever for me to believe. I am going to be me! Same sense of humor, same likes and dislikes. I am going to be me, although I will be me in the outward expression that I choose closest resembles my soul. Trying to think of myself as a different person caused a LOT of grief. I can't tell you the release I felt when I finally knew that I would still be me. the duality was gone, and as such, so was the fear.
Sometimes I get a little long winded.... but hope this helps. Just a different slant on it all.