I know it's bad because I ask what she wants to do in life, her hopes, her dreams, and she says "cease existing".
She needs to deal with THAT before you can hope to have anything. If I were you, I'd sit down at a time that's calm for both of you and tell her that you want to talk about something serious. Start out by telling her how much you love her and then let her know that "cease existing" as a goal is something she should get help for. If she agrees, you may have something here. If she doesn't, I think you're in for a rough rode ahead.
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I just read your latest entry. I guess I don't understand why her watching a religious program is making you so upset. Forgive me if I'm being rude, but it sounds like you want to control her. That doesn't ever work. If she knows that watching those programs pushes your buttons then there you have it. Why would you want to be with someone who pushes your buttons. On the other hand, if she is just confused about her spirituality, then are you ready for that ride? You can't tell her what to do or make her believe this or that. Her journey may bring her back into the cult and then back out again. There's no way to say. If you aren't ready for that or no you don't want that, then you need to have the frankest talk you can and make a decision.