My tuppence worth...
Full disclosure happened a few months ago for me. She's known I've had doubts for the last year and that I've been discussing them with some elders and had no satisfying answers.
For me, even though I'd been told not to talk to my own wife about my issues (!) I couldn't cope with the dishonesty of it all, the hiding of my inner thoughts, and just figured she deserved to know the truth about how I felt.
I told her I didn't believe a weird of it anymore, there's no way we were god's one true organisation, but that I was keenly aware of the devastating effect my leaving would have on our lives, family and social etc... So I said I was willing to put up a pretense for her sake and just do the bare minimum.
I really do love her, and my hope is that her curiosity will kick in at some point and she'll ask some questions about why I don't believe. I won't press the issues, she's got to want to research it for herself, but I'll be ready for any questions when they come.
If after all that she decided to carry on being a witness, that's her choice, but I can't see me doing it forever.
Anyway, I've toiled with this 'full disclosure' question for years, I've got to say it feels great to be utterly out in the open about it . no more making excuses for myself about missing ministry or meetings, she knows exactly how I feel and will be expecting a lack of enthusiasm for all things spiritual.
And hopefully she'll see I'm being more than reasonable in the process.
Full disclosure ftw!