This is a great question, Moni!
My case might seem a little odd, but it is largely a product of my age and upbringing. It was a two part process, recognizing my true nature, and deciding to transition.
I recognized my nature over 30 years ago. The childhood 'cure' I had gotten was wearing off, but I didn't know what I was other than what I had been told, nothing good. I was definitely in hiding, even from myself. We were interviewing folks for a position on my engineering team, a rather grueling all-day interview process. One of the candidates was a transwoman who, unfortunately by the end of the day, was showing a 5 O'clock shadow. I remember sitting there talking with her about the opportunity and our needs, when the thought popped into my head that "She's so brave. I wish I could do that."
Wait. WHAT??? My sneaky subconscious had just outed me to myself.
Given my childhood rearing, shame and repression came easy to me, and I resolved not to hurt my wife and young children, and take this to the grave. I almost made it.
In March 2016, just over a year ago, I planned to end things. My mind was crumbling, my core being corroded away from repressing this. I called a hotline in desperation, and was talked down and quickly placed in therapy. I got treatment. My spouse and I negotiated terms for what I could do. They were restrictive, so restrictive that I broke down again in a few months. I convinced her to let me try HRT. I started seeing a gender therapist. Finally, I reached the point where I knew I had to stop putting everyone else first and myself last, and had to take action. My spouse told me this wasn't working for her, and I'd have to leave. I resolved that if I wasn't living under the same roof as her I would immediately go full time and transition.
I did. I moved out on October 22, 2016 and immediately went full-time.