I transitioned. You're not volunteering to lose friends, family, and it all. You're instead saying you love yourself enough to face whatever storm of bigotry there is out there - including the storm of transition. It's much more self-love and a refusal to be a slave to a system that doesn't want you to be happy in life because of who/ what you are.

A lesson in life is to truly love another, you have to truly love yourself first. Transitioning is an act of self-love first and foremost. An act of self-acceptance, and in the face of - you're right - sometimes of great opposition. But on the other side you'll know who truly loved you and accepted you and who didn't.

Contrary to a lot that's being said here, you could hide it for a long while, years to be honest, but not easily. Especially if you go DIY route and just get the mones yourself. But to more completely transition, including legally, socially, and possibly if you want srs, that will require involving the system.

That said, if you are in the process of biological transition (HRT) and you are married, if you want to have any chance at keeping your wife you need to tell her. You might lose her because she's true-blue heterosexual, and she has ever right in the universe to not be attracted to another female body - and that is the point of biological transition from male to female, to have a female body, and she may or may not be compatible with that. If you keep your relationship post transition you've put you both in a same sex relationships. But if she does truly love you, even if she can't sexually / romantically be with another female, she will most likely be your best friend and there for you all the way.

I kept 95+% of my family and friends. Most of the ones I lost I cut out myself, because either I had old male friends who were being creepy chaser~ish to me, or they just had too much cissexism and I didn't want to have to be the Cis Whisperer for them.