Hi Lil Red, When I dropped the bombshell on my wife it was one of the hardest things to do but a massive relief afterwards. She is still struggling with the loss of her husband, who 'I am' and where I am heading as that path is not yet defined. I buried my desires for 30 odd years and regret doing that as I have missed out on so much of my REAL ME.
I would think your husband will understand but he will be hit with waves of different emotions as my wife did.
You definitely need him alongside for this journey as it can't be done on your own while in a relationship.
Finding the right time is up to you but sooner than later helps. As for telling the rest of the world, small steps in line with seeing the therapist as you will be wanting to change things about yourself that others will slowly pick up on.