Alice,
When I went to my therapist for the first time it was because my anxiety and depression over what I discovered about myself were beginning to overwhelm me. I did not, however, decide to do a full blown, 100% transition at that time. I decided to take steps: therapy, going out dressed the way I like, then HRT, to see if this was really a thing I needed to do. All of these things were, if need presented itself, reversible.
It was only a couple of weeks ago that I came to the conclusion that, although this will affect many parts of my life negatively, I have to do it. I have to make the final portion of this journey.
I don't think a person can be "stable and happy with [their] life before and decision on transision" when full blown GID is present. Yet there are still times when being a man in the outside world has its benefits. It pains me now to know why those benefits are in place, simply because of my perceived gender, but they are still pretty nice to have for the time being. So perhaps this is what you are perceiving as being happy as a man? Besides, everyone's journey is different and their best destination is different too. Completely changing your gender presentation may not be the best thing for you to do. Perhaps your mix of gender feelings is what you need to accept, rather than transitioning all the way?
Whatever you decide, Alice, will be fine, as far as I'm concerned. Keep workin' at it,
hugs & smiles
helen