Depression and anxiety. Tell your wife and friends that you have headaches before the meetings. Arrive a little late, leave a little early and cut back on field service. Fake some hours, too if you want to fade slowly.
Work on your marriage - and actually *do* some fun stuff with your wife. Maybe keep up a family study - but consider just reading the bible.
If you have children - start doing more fun things with them. A weekly family hike. Just make sure that the activities don't put *more* pressure on your wife.
Take a class. Maybe it's something related to work. Some companies will even reimburse tuition and book costs. Or take any class that you are interested - but tell people it's for work. Or that you are working on a degree (if you don't already have an advanced degree). I read here somewhere that if a servant's children were going to college (or that a servant was encouraging others to go to college), it was grounds for removal. I would imagine if the servant himself was attending... He would likely be expected to 'step aside' or be removed.
I agree with the others about expressing doubts. Don't do it. It will cause more troubles than it solves.
-Aude.