I don’t want to take over some random 18 year old’s post but I do legitimately wonder how to make sure anyone I’m in a long term partnership hasn’t drunk the anti coolaid.

My personal advice is to make that part of the “getting to know you” early dating stage of the relationship.

It’s easy, casual and normal to talk about what type of fiction a person likes and dislike, and what sort of attitude they have toward censorship, and toward fandom.