YES, they get married.
Dan Stevens said so in interviews. I wish I had posted to them before, but from memory, he says that he didn’t see her wedding dress until the “walking down the aisle” scene, so that reaction is unrehearsed; also, there’s BEDROOM SCENES!
Bedroom scenes, people. Good ones, meaning, presumably, Matthew doesn’t go all Mr. Pamuk on us. 🙂
So, relax. They’re getting hitched.