EDIT: This turns out to be more of a "coming out" post than a therapy post. Mods, feel free to move if appropriate.
So I finally came out to my therapist, after several weeks of agonizing. What a great experience! She's understanding, compassionate, and fully invested in helping me figure out the best way forward from here.
So now I'm in a place that's really exciting and really scary at the same time. My therapist doesn't specialize in gender issues, but she's consulting with her colleagues who do, and we're learning together. She's already connected me with some amazing local resources including everything from support groups to a voice coach to a local doctor who's trans herself and does hormone therapy. Suddenly, it's all real.
I feel more than a bit guilty for being as thrilled as I am about all this, because the first step in the process is going to have to be coming out to my wife, and while she's a wonderful and supportive person I'm scared to death of this. Even if she stays with me as I hope she will, it's certain to cause her pain. Do I have any right to be so happy about the future when I'm sitting on a secret that could be devastating to her? I feel awful.

But at the same time, I feel hopeful about the future for the first time in years. This could actually happen. I could actually be accepted for who I really am.
There are some unrelated family dynamics that make it best for me to wait a month or two to tell her, but it's got to be soon. I don't want to leave her in the dark. My therapist recommended that I reach out in person (via support groups and such) to some other girls who were married when they transitioned. I'll be doing this as soon as I can.
So I guess the takeaway is that I don't know whether to feel elated that I'm finally taking some concrete steps, or even more depressed that I'm going down a path that could put my marriage and family at risk. I hope I'm not an awful person for going ahead with this. I just don't know how much longer I can continue living as someone I'm not.
Liz