Check_Your_Premises: Maybe I will write a different version that is more of a refutation.
That may be a good idea, but you are nearly guaranteed to alienate your spouse. Sincere questioning is probably the best way to go.
Lead in some days before letting her know you've been thinking seriously about where your life is heading. This will be entirely genuine, of course. You simply need not mention you are afraid this org will rip you two asunder. But just say it and leave it there. Any wife will wonder long and hard about what you mean.
Follow after a couple of days by asking, "Okay, if I have questions about their beliefs they can give me scriptural answers, right?"
She'll readily agree (poor dear).
Invite "them" over for a discussion (you know who "they" are).
Have your questions well in mind, we will all be glad to prep you as much as you like. Make sure "they" are trying to provide scriptural answers in front of your wife. This way, you are not attacking her at all. You aren't even attacking "them." You are just allowing her an opportunity to see the gross inadequacy.
Respectfully,
OldSoul (of the "Going Through the Same Thing" class)