One very typical beat for a fictional romance is one or both the partners
being “tempted” in some way by another potential partner.
There was a character in The Walking Dead who reminded Rick Grimes of his deceased wife Lori, a development which many fans thought spelled the end of his potential romance with Michonne. Princess Leia kissed Luke in ESB, something I’m sure we’d all like to forget
about. The Hunger Games had the typical YA love triangle which I
read the author didn’t even have in the original version–Gale was
originally Katniss’s cousin, not her potential love interest (Katniss
still comments on their physical resemblance in the book), but the
publisher wanted the triangle to spice things up. That’s how common a
trope it is.
Looking at these examples it seems to me that a lot of these
“temptations” from love have to do with family in some way, or the
unhealthy, traumatic aspects of family dynamics. Rick’s wife Lori
cheated on him and died in childbirth. leaving him to grieve for years. The woman who
reminded him of Lori (I’m so sorry, I can’t remember or find her name)
is an obvious callback to that complicated trauma. Leia and Luke for
obvious reasons, even if the familial relationship was a retcon. Gale,
even when he was no longer Katniss’s cousin, was still explicitly tied
to her identity as a provider and protector to her family. He
foregrounds this himself by saying how her attraction to him, to the
extent it existed, came from knowing he would take care of her family.
Given that Katniss’s need to provide for and protect her family,
especially her sister, from a young age not only drove her character
from the start but was the source of many of her issues and traumas, her
relationship with Gale was similarly based on this unhealthy part of her
family dynamics.
From these observations it seems Finn’s and Rey’s separate plots in TLJ, specifically with Rose and Kylo Ren respectively, have much more in common with temptation plots than endgame love stories. I say “temptation” here as more a plot element than a subjective psychological experience of being tempted. The temptation plot often does come with personal attraction, but in Rey’s and Finn’s cases the attractions do not seem to be romantic or sexual. Rather they seem attracted to things that are promised by or come to them through the tempting character, such as turning a powerful Force user to win the war, or the promise of comfort and freedom.
With Rey, the callback to the unhealthy/traumatic family dynamic is obvious since Ren uses her abandonment and family issues to try and tempt her into changing sides much as Vader did with Luke. Not only that, Finn’s relationship with Rose also reflects an unhealthy family dynamic, but with his upbringing in the First Order rather than his actual family. This may or may not be intentional on the writer’s part, but Finn’s first meeting with Rose is characterized by the compulsion, backed up with violence, to stay with an authority he is trying to leave. That original wrong is never addressed in a meaningful way but evidently accepted as part of the working relationship.
Even when they become friendlier Rose talks down to Finn at crucial points, impugning his courage and intelligence. (If you want to tell me she was joking, please see Tangled for what these “jokes” can do to a person. Maybe watching a blond girl being subjected to this treatment will help you see it’s harmful.) When he charges the cannon on Crait she again stops him with force. It is an accepted part of their relationship in TLJ, then, that Finn is lacking must be taught by the wiser and more knowing Rose, by violence if necessary. This calls to mind the constant berating and strict regimentation he endured in the First Order. The best thing he can do is tamp down on his own instincts and follow her lead, or he will be hurt–for his own good, obviously. This is the opposite of his storyline in TFA where Finn for the first time in his life acted in direct defiance of authority, both the First Order and Resistance.
TLJ, then, saw both Finn and Rey be tempted away from each other–not just as potential love interests, but also as co-heroes trying to break away from their respective traumas. They were both retraumatized in some way; Rey’s self-worth was questioned by an unsrupulous character who wanted to exploit her talents, and Finn was presented with the choice of either fully complying or being hurt by someone who “knows better” than he did. These dynamics are in direct contrast to the unconditional acceptance and affection Finn and Rey had found in each other during TFA and constantly yearned for in TLJ.
Finn and Rey’s unconditional love held true even in disagreement and conflict. When Finn wanted to leave in TFA and Rey wanted him to stay, he didn’t tell her he was the only person who could love her and she would be alone if she didn’t come with him. He sadly accepted her decision and told her to take care of herself, because clearly she could and she had friends and allies as well. Rey, though so saddened she couldn’t even bring herself to say good-bye, did not assault Finn or deride him as a coward; she let him go, because it was his decision and, if a mistake, his own mistake to make. That’s what it looks like when you love someone as a free individual and not an object to control for your own ends. It is the only way to love.
The respective temptations of Finn and Rey in TLJ, intentionally or not, serve not only as bumps in the road common in love stories but go to the heart of their characters and traumas. This is because the story of Finn and Rey’s love is about overcoming trauma and growing past it. And it is a love story, whether you think of it as romantic or not–it is the central relationship of the sequel trilogy, and that won’t change even if they have other or no romantic interests. Their story in TLJ was of them being tempted, in one way or another, from the true path of love. With their reunion the next part of their story begins, to extend their realization and growth into the galaxy at large and help others out of danger, trauma and hopefully servitude. The way may be hard, but together there is nothing they cannot do.