I think Rey may be influenced by the power of the Dark side, but here's my guess
In Episode VIII Kylo and the Knights of Ren (that sounds like a band name now that I think about it) are hunting Rey and Luke while Luke trains Rey. Kylo finds Leia, spares her, finds Luke, kills him, and takes Rey to Snoke. I think it will end on that. In Episode IX I think Rey and Kylo will fight Snoke, escape together, go planetside, Snoke finds them and it ends in a big duel with Chewy or Leia dying. Maybe Kylo too. But I think both Kylo and Rey are in the grey area of the Force and both will change, but together. Maybe the love triangle will be between Rey, Finn, and Kylo and not involve Poe after all.