Kylo Ren is forced to work with the Resistance, perhaps joining them to defeat Snoke, or to defeat a greater evil that threatens both the New Republic and First Order, or whatever. He isn't there because he had a change of heart, but because he's trying to save his own ass.
Working with the Resistance leaves him full of anger that he just can't seem to channel into anything, and it's becoming a risk and a hazard. Cue Poe - beautiful and loyal and a perfect vessel for Kylo to work out his aggression (sexily). Maybe Leia orders Poe to, maybe she strongly implies it, maybe Poe can't stand the idea of her knowing. But he does it for the good of the galaxy.
The real problem is when he starts to like being hurt.
Kylo Ren/Poe, dubcon
Working with the Resistance leaves him full of anger that he just can't seem to channel into anything, and it's becoming a risk and a hazard. Cue Poe - beautiful and loyal and a perfect vessel for Kylo to work out his aggression (sexily). Maybe Leia orders Poe to, maybe she strongly implies it, maybe Poe can't stand the idea of her knowing. But he does it for the good of the galaxy.
The real problem is when he starts to like being hurt.