I'm see you took a camping "time out" for your mental health. You sound a bit better.
It seems you have decided on some initial steps like not seeing the wife, choosing to accept what is happening etc. That's good -- moving it forward.
Hang in there as you try to arrive at next steps. Remember you don't have to do it all in one go, take it one thing at a time. Consult who you have to consult along the way.
Even though you seem to be moving towards a divorce and working your way out of it, you are still inside the polymath
and what one person does can affect the others. The "ripple effect" thing can still be felt. Could remember that, esp with the kid inside the math in there somewhere. This all affects kid too.
You don't have to stay in a marriage that is unfulfilling for sake of the kid, but could take the kid's transition into account and support kid through the change as best as possible even while supporting your own self.
You can get through this. Hang in there.