I would describe the times when I am "okay" with being male as the times when I am coping well. I never had a problem with being male in the moment, but I cannot bear to be male in every moment. I built my whole male identity around doing, starting with the fact that I presented as male to make people I cared about happy (or to keep them from worrying about me, or worse, thinking I was damaged goods). There are some things I can do where it does not matter what I am, and there are things I do because they have to be done no matter how I feel about it.
There are a lot of things that can blind side me and turn me into a complete, paralyzed wreck. Being around girls can turn me upside down, it only takes a moment to see myself in a girl's shoes (so to speak) and as soon as I do, I am hit with the reminder of all the things I am denied because I am not female. At other times, being seen as a man by someone, anyone really, can tear me apart, because in that same instant I see myself through their eyes and what I see is not me. The same thing happens when I see my reflection or a photo. It does not matter much where I am or what I am doing, the feeling of not being me hits like a splash of ice water and suddenly I am fighting to assert my own identity in a situation where I really cannot assert myself.
There was a time when I thought of myself as an invisible girl with an autistic brother. I was always me, but no one ever noticed I existed, and I spent all my time protecting and taking care of my brother, keeping the world from noticing that he was not all there. Eventually, I realized he was the one who did not exist and trying to make it seem like he did was destroying me. In spite of that severe dissociation, the realization allowed me to see that the man I pretended to be for so long had always been a part of me, and in a lot of ways, I make a really great guy. I can be him for hours, days, even weeks if I have to, but the moment I stop acting, I am just me, lost, alone and unknown.
Being him gives me something to do to distract myself from the fact that nothing I can do can make up for what I've been through or for what I've been denied. But, I can only be him when I have the strength to endure reality. I'll be honest, it is much easier to pretend to be him, and be seen as a really great guy, than to try to be myself through him and be seen as a tragic, twisted and confused freak. I spent too much time learning how to read people, particularly men, to not understand instantly how people see me. I say that only to point out that I would find it easier to stay male, be the man I appear to be, and be thankful for the life I've got. It is easy to tell myself I am okay with this, that I've grown up and I am better off being the man I spent a life time learning how to be than I would be trying to become a woman who missed out on all the experiences she needed from life.
It sounds logical, but to be that man, I have to cease to be myself. It's not hard. It's like holding my breath... um... yeah, not really a good, long term solution. Why does the girl in you keep coming back? Well, she's telling you to "Breathe, Idiot! Breathe!" You can be anything you want to be, anything you can find in yourself, as long as you don't deny who you really are.