You are not "screwed forever" unless you let yourself be.
Tell her in no uncertain terms, "You are my wife and we are going to be together. You do not get to give me ultimatums in regards to what I will do or what I will believe. If you can't live with me under these conditions, then let's be clear: YOU ARE ENDING OUR MARRIAGE. Not me. Don't play any games, they are for children.
If you can't or won't accept me as I am, then you--yes YOU--are a messed up person."
If YOU separate from me, then I understand that I will be free to pursue whatever course of action(s) that I see fit to live out the rest of my life as I see fit."
I'm not sure where you got all twisted up in your thinking, but conditional acceptance is not love. I want, indeed: I deserve to be loved unconditionally. I will accept no less. If you cannot or will not do that, then I'll find someone who can or I'll live alone, but I will not be manipulated and controlled by someone that doesn't have the faintest clue as to what real love is. Is that clear? Good."
What? You're gonna' tell the elders! Be my guest. If you are more attached to a loony old guy that is fixated with men in tight pants and colored socks than you are to me, then you deserve whatever you get. ... What's for dinner?"
And whatever you do: DO NOT GET ANGRY!
Be calm, be firm, be loving. Your position is one of absolute moral integrity and is therefore non-negotiable.
She's the lunatic in a religious cult. Don't forget that.