Here's my advice, given your circumstances:
It starts with an exit plan and that means a real "plan." Write it out if you have to. Imagine how someone like you could get out with as little collateral damage as possible, then execute the plan. Part of this plan is to take your family with you so you have to have a serious talk with your spouse and/or children.
Once that's done, the first step is to stop being an elder. In your position, you can't just walk away. You have to surrender the title. Most subtle way to do this is to blame it on circumstances; it's best if someone is sick. In my case, my wife came down with an illness that can either run its course or get much worse and become chronic. Even though the odds were heavily in favor of a full recovery I let everyone know what the worst possible scenario was and portrayed that as the likely outcome. If that hadn't come up so conveniently, then I would have created some other excuse - for instance, once I went in for a physical and my doctor suggested a full cardio workup and sent me to a cardiologist. Had I been ready to leave then, I could have said "I'm seeing a doctor about my heart condition; there may be a problem."
Then I took started missing most of the meetings to stay home with my wife and cancelled a couple of upcoming assignments. After three or four weeks of this, I went to a meeting, took the PO aside, and explained that my wife's condition was going to require a good deal of attention for many months to come, perhaps indefinitely, and that I could no longer serve as an elder. He made the usual sympathetic noises and said he would inform the body of my decision. I hadn't been in the cong very long because we had changed halls some months earlier - which was not consciously part of my exit strategy, but in retrospect it probably helped with their ready acceptance of my resignation as I wasn't part of the Old Guard in the new congo.
Our meeting attendance after that was spotty at best. Finally, about five months later we woke up one Sunday morning and realized we had not been to a meeting in more than 3 weeks. "Are we ever going back?" my wife asked. "I would be fine with never going back," I replied. She thought for a minute and then turned back to the Sunday newspaper and just like that, we were done.
I screened all phone calls and told the few (surprisingly few) dubs who inquired about us that "health issues" were keeping us from doing "all that we would like." After awhile, the queries stopped.
In the meantime, we took advantage of the free time to develop new friends and new interests. Now it's been nearly six years and no one has ever bothered us. I think in part that is because I understood the system and played it well; by that I mean, having seen a lot of dubs disappear over the years, I analyzed how they faded and anticipated the repercussions and carefully planned to avoid them.
I think if you've been a dub for a long time, you can pretty much figure out how to escape. The problem is making the commitment to go and the willingness to sacrifice some things (and some people) that you've held dear for so long.
For us, the price has been worth it. We are fully in the light now and see 'The Truth" for what it was. We would never go back.