Just my opinion but, I think you're on the right track waiting to talk to your wife until you are fully prepared to do so. However, I would suggest that you NOT try to hide going to therapy.
Women often don't react well to finding that her man has been hiding things from her. Try giving her some general reason for therapy, like "mid-life crisis" (are you old enough to have one?). Thats not really a lie, since many of us didn't begin dealing with all this till mid-life.
Seems I've got to have a change of scene
Every night I have the strangest dreams
Imprisoned by the way it could have been
Left here on my own or so it seems
I've got to leave before I start to screamJoe Cocker