So my S.O. just informed me she may be joining a fundy church

[Zoomie1986]

49. I can tell you now that your relationship is probably over.

The time to counter the influence of these emotional vampires was the first time she mentioned any interest in what they said about jebus or their church. Once she's at the going to church phase, she's lost to you. It's useless to expect her to change, and you will have no peace with her now that she's gone this far. She's only going to get worse by becoming relentless about dragging you down to her level with her.

Nothing you say, nothing you show her will persuade her that the church or the sect or whatever could be harmful. The first thing her cult programmers did was convince her that any criticism of the religion was not to be trusted, because it was the work of Satan. They are already well on their way to convincing her that as long as you are not joining her in her conversion, you are the enemy, a liar in league with Satan.

The book they follow is quite explicit about how they see anyone who doesn't agree with them:

Think not that I am come to send peace on earth: I came not to send peace, but a sword. For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law. And a man's foes shall be they of his own household.

That's where you stand now. It's right out of the mouth of their deity. Matthew 10:34-36.

Unless you want to become part of the cult, get out now, and never look back. Nobody is worth the aggravation you'll endure if you don't.