I've always seen it described as Freytag's Pyramid. (Possibly because of a subconscious belief that climaxes occur when you're on top of pointy things.)

However, non-fannish novels, plays, and movies are notorious for ending with the wedding, even though the couple then have years or decades of challenges to face.

There are a lot of open endings, either because the writer can't figure out what comes next, or has a philosophical belief that it isn't knowable. I have to confess that intellectually I'm not convinced by an ending that ties up all the loose ends too tidily. But emotionally, I'm not satisfied by an ending that just trails off without resolving them.