I'm sure that Rey and Finn will be reunited at some point in the movie. Their relationship was important in TFA and will continue to be so for the remainder of the trilogy.
I also think though that the next film will be largely about Rey's Force/Jedi journey, exploration of her newly discovered powers etc., and I don't know if Finn is meant to be a big part of that. I've seen theories about Finn being force-sensitive himself, but I doubt we're going to have two young people awakening to their powers. So it just makes sense to me that, in the next film, Rey could be spending a lot of time around her fellow Force people, most notably Luke. And I'm guessing Kylo Ren will track her down at some point, as well.
I also think though that the next film will be largely about Rey's Force/Jedi journey, exploration of her newly discovered powers etc., and I don't know if Finn is meant to be a big part of that. I've seen theories about Finn being force-sensitive himself, but I doubt we're going to have two young people awakening to their powers. So it just makes sense to me that, in the next film, Rey could be spending a lot of time around her fellow Force people, most notably Luke. And I'm guessing Kylo Ren will track her down at some point, as well.