Don't know how old you are and we all understand what you're going through, we've been there, trying to please everyone in the family by faking it.
The conclusion of the matter is since you know that the watchtower is a cult, in due time you will not be able to keep your mouth shot and eventually hell will break loose with your wife, your parents and the congregation.
I slowly faded, my marriage fell apart after 26 years but i am free and living with a clean conscience being away from a dangerous religion.