Hi jwbot...
I too "know how you feel".... I am in the exact situation that you describe, and I AM faking it. I go to the meetings, sit in on studies, talk all the b.s. when in the company of my family. And of course they are accepting of me now, after almost twenty years of silence.
But I have kept one thing in mind during all of this. The "love" that my family is showing me is just as fake, as my pretending to be a dub. It was like flipping a light-switch when I went back to the Hall..... I "turned them on" and when they find out I am faking it... the switch will undoubtedly be flipped right back off. I hope by then, the "damage" I intend to do will be done.
I began this thing with intentions of rescuing my family from this monster. But each day that passes... I feel exactly what you describe... immoral, un-true to myself... for just pretending to "show support" . It makes me physically ill. Each time the meeting is over and I come back home to my wife... I just feel a weight off of me. I wish you all the luck with your family, but I can tell you from real experience, that faking it, won't help. It will only make you see through them even more.
Agrees with Drwtsn though.... it is emotional blackmail... don't let it get you.