I think there is definitely an attraction and an intentional intertwined "Star Crossed" destiny with this pair, and The Last Jedi had some sexual subtext (Shirtless Ren, Rey touches his thigh), but The Last Jedi leaves viewers still somewhat ambiguous about Kylo Ren's overall motives or philosophy, not to mention it feels like there could be a love square brewing between Kylo, Rey, Finn, and Rose.
(Also Note: Star Wars Novel, LOST STARS and it's love story between characters who end up on opposite sides of the conflict).
However, it was reported that J.J. Abrams is pitching his general ideas for episode IX to Disney head Bob Iger. Allegedly the code name for the film is currently, "Black Diamond"
Black Diamond Symbolizm:
Black Diamond Lore
As a real, natural diamond, these stones share
all of the same meanings and symbolism as traditional white diamonds,
such as strength, wisdom, eternity, and everlasting love. Italians in
medieval times believed that black diamonds wielded the power to
restore the relationship of a married couple, and the Black Orlov
diamond had a reputation for bestowing happiness and good fortune on
anyone who touched it.
Black Diamond Metaphysical Properties
As kings of all crystals, black diamond possesses deep metaphysical use and purpose. It is often
used as tool to open doors to the spiritual world. That explains why a
lot of healers and cleansers use this stone at their work. It allows
for spiritual communication as well which is sometimes needed by those
who look for truth. http://gemstonemeanings.us/black-diamond-meaning/
Given the way The Last Jedi ended ('spark of hope'), it seems likely that episode IX is going to be a hopeful tale by the story's end.
In addition this story is still clearly about Rey stepping into the Skywalker Family Saga and therefor it has to have conflict resolution of some sort between her and Kylo Ren, despite that I think we still don't fully understand what the nature of their roles are and/or are in relation to each other.
But if we read into the symbolism of the Black Diamond, then it seems likely that this is a story about compassion, healing, and everlasting love and perhaps with some literal metaphysical advancement on [kyber] cyrstals (ie Snoke's Ring), Force Ghosts, the afterlife, and/or immortality and that Rey is probably going to try and save Ren, or Ren may try to save Rey, or they may face something bigger than themselves that forces them to work together.
The Last Jedi Novelization:
There's also some information from The Last Jedi Novelization author Jason Fry that may also support some kind of love story...
"Lots of fans assess it as a potential romance, and maybe that’s
ultimately what it will be. (I have NO idea.) Certainly the famous
scene in the hut verges on that.
But we fall back on romance because it’s the best analogue we have.
Rey and Kylo’s relationship is more intimate than that. They’ve
literally been in each other’s minds. Rey’s seen his deepest fears;
he’s seen the past she’s buried. None of us have had that experience.
My point is romance may not be the endpoint of that. (Though it may
be.) The analogue may be misleading, because it’s an analogue. Their
connection is deeper and stranger and far more complicated. I think
TFA/TLJ covers those complications wonderfully, with Ep IX promising
If we take what Mr. Fry is saying here to heart, he may be suggesting that "romance" is the closest thing we have to describe their feelings for each other, but that he feels whatever the end results of this relationship really are, what they have runs deeper than romance, being extremely intimate on a profound psychic and/or emotional level.
I think he's saying, there's romance, but then there is also love, but love tends to either bring people together, or rip them painfully apart and therefor it's hard to say where the chips are going to fall, given everything we do not know about episode IX.
This link from Star Wars' own official website, also provides some insights from The Last Jedi Novelization, making it more essential to see where things could be headed, including suggestions of a Kylo Ren/Ben Solo redemption arc.