Your wife is smarter than I was! It took me 15 years AFTER my husband left for me to leave. When the kids and I finally left, Chris was working nights so the kids and I would read a chapter from the Bible at night. We started with Matthew, and we used a side-by-side 8 translation Bible that Chris found -- it was most revealing! The vernacular of The Message next to the King James Version was kind of an interesting comparison and it gave us a different viewpoint of familiar scriptures.
What became very clear was how simple Jesus' message is: love God, love your neighbor. That's it. That's all it takes to be approved by God (whatever his/her/it's name is) and keep a person a functioning member of human society. It was a beautiful revelation. Nothing else really mattered after that, and the rest of the NT began to look like a bunch of guys trying to start a religion and imposing THEIR rules but claiming it had to be from God.
Try to make your wife see that you are not leaving God (Jehovah, in her mind) at all -- you are merely stepping back from a group of imperfect men who got it wrong. If the original Christian church, started by men who actually KNEW Jesus personally, could degenerate into a bunch of sects, then why can't Jehovah's Witnesses also be guilty of apostacy? What makes them so special? Hey, I could call myself the Queen of England, but that wouldn't make it so!
Moving will be a very graceful way to fade. You might even consider having the elders send your publisher record cards to the wrong congregation in the new place (oops!). If they're anything like the ones in my area, that should earn you maybe one visit every couple of years -- if they remember.
Nina