Go slow. Go slow. Go slow.
She doesn't fully realize it yet but you've just removed a huge part what she considers her life's foundation. You have to move slowly.
Help her to realize, by being an extremely great husband, that you can be the same husband she married and loves even though you aren't a dub zealot anymore - and soon won't even be a dub.
If you rush you will send her running to the elders and all the painstaking work you've taken your time to accomplish will be gone.
Stepping down is hard but managing to maintain your marriage through the rest of the fade is the really hard part - because your wife lives with you and knows you so well she will see through any smokescreen statements about stress and family obligations.
I let my wife know I wasn't comfortable with all the changes that were taking place and how the WTS handled them. I had doubts/concerns and wanted to research some stuff for myself. She gave me time to do that. I also clearly told her that if she wanted me to talk to the elders I would but I wouldn't just accept their word as answers and they don't have any additional information that I didn't have so I would probably be disfellowshipped after a couple of visits with them (because they would answer my doubts but I wouldn't just nod my head and let it go). She let me research on my own which slowly slowly slowly allowed me to fade away without having to deal with anyone. Anytime I got a question from a friend or family member I just said I didn't want to discuss it because it was so personal and that if I needed to talk to the elders I would - fat chance that would have happened but it worked to keep everyone off my back.
Your duties are off of you so you can be a seat warmer at the meetings, when you go. Just don't make any sudden moves or statements.
Best of luck. Of course, all of this is just my opinion.