Loved your story, Tara! I, as many here , can relate to the desire to chicken out at the last minute. The biggest I had was getting my hair colored, dressed in fem, and coming out to the first pf my 4 brothers. These went well so I desire to do more and come out to more ( so far 3 of my 4 brothers ).
For you unless you can go down deeeeeeep into the closet and be content to stay there you are right that you need to make a plan to come out to your wife. From every story I’ve read here that it depends on your personality you may go into depression or into addiction (drugs and alcohol ). Get some of your responses ready and pick a good quiet time to be honest and open with her and be sure you LISTEN to all her concerns. She is so likely to be confused and maybe hurt you may hear the same question more than once and explain yourself about the same thing lots and lots. If you can keep in you mind your love for her and keep reassuring her of your love for her and you never meant to hurt her. Good luck to the both of you. We are all here to listen and offer advice.