Thanks for updating Stevie. I wish you all the best. This is a massive thing, I think you know that. I am sorry you felt shame about this and wonder if you ever looked for any 'help' or counselling about it. Either to stop or to get comfortable enough to be open about it.
You do not need to answer this if you do not wish to, of course.
I think one factor is that although it may be better for your wife not to know, would you be able to take this secret with you, and never tell her? If you know that one day you would tell her, then I think it is better to do it sooner rather than later. Better for her, maybe, although maybe not better for you.
If this does end your marriage then I think at least now both of you would have a chance to find a partner: you - who you can be honest with; she- who can be honest with her.
She would also have a choice to stay with you knowing this. If you wait until 'old age' to reveal your secret then you may end up staying together as neither of you has the energy or ability to leave.
Wallywobbles said "In her shoes I'd rather not know ever." And I kind of feel the same way, but I wonder if the pressure to reveal the secret may get more and you may find that in the future you do feel a compulsion to tell her. So not telling now, although it may appear kind to her (and to you) it may actually delay the pain.
I am really not sure how you feel your wife may want to be part of this as you say you do not want to do this out of doors and it is not sexual. I also think you may need to think about this, fake breasts doesn't sound non-sexual to me.
There may be a small number of women who get involved in their partners cross dressing etc but I do kind of feel your chances of finding such a person would have been much higher when you first met a partner and they accept this side of you at the start, with the whole package. Expecting someone to accept this now, over two decades on, that seems rather wishful thinking.
Please do update us. Much as my sympathy is with your wife in this, I do wish you well. 