Thank you all for the kind words. Here's the rest of the story.
By March, 2012 I had lost over 50 pounds, was eating right, walking several miles a day and practically none of my clothes fit anymore. For years my preferred "uniform" consisted of track or sweat pants and a t-shirt, and my wife thought that it was time for a change. I had always hated wearing shirts with buttons, slacks, jackets and ties, but I thought that since I'd look really good in nice guy clothes once again, that I'd give it another shot. My wife kept commenting on how skinny I was, so I went out and bought some really nice designer clothing that fit well. Objectively speaking, I looked better than I had in years and was now paying more and more attention to my appearance. I started to lift weights, and over the summer I remodeled my kitchen, working hours of physical labor every day. By the end of the summer, I had put on about 25 pounds of muscle. Apart from the hair I was now losing at an alarming rate due to an endogenous testosterone level increase, I looked the best I ever did as a guy. I tried so hard to own it. I knew that my beautiful, long hair that I had for years was about to need to be cut short, and it depressed me. Instead of loving what I saw in the mirror, I actually hated it with a passion. My dysphoria was the worst it had ever been. I couldn't look at a woman anymore without feeling the emptiness inside, and I began to think that dream of being a woman someday was over and the transition boat had been long since missed. I figured that I would now have to settle for losing the rest of my hair, remain a guy forever and put any notion of being a woman out of my mind forever. *le sigh*
In early fall, 2012 after having a few drinks, my wife and I decided to play "dress-up". She put on a sexy outfit and some goth-y makeup while I donned nothing but a kilt, boots and leather biker jacket. Since I pretty much looked like an aging rock star, she thought I needed some "guyliner". When I saw myself in the mirror, I just wanted to die inside. I didn't see a guy looking back at me, I saw a sad, sad, woman who never once got a chance.
That moment will haunt me for the rest of time. I knew for sure then and there that I was truly, undeniably some kind of gender variant. I did not think that I could realistically be transsexual material at that time, but I felt the need to explore things further before I could admit anything to my wife and potentially end my marriage. I fell into a deep depression and spent much of the next month alternately researching transgender issues on the internet and crying in a fetal position.
As soon as I could accept the fact that I truly belonged under the umbrella, could say it out loud to myself and no longer cared about the consequences, I told my wife.