Ok. Reylo. Let me explain:
Ben Solo, due to lack of trust in people caused by his own Uncle's attempt to kill him, means he has never experienced the sensation of love. So, when he starts to feel an attraction to a scavenger girl whom is his enemy, he uses it as a warning sign.
The same can be said for Rey, who's trust issues stem from being abandoned on Jakku by her own parents, as she has never experienced love before. At first, she believes that Ben Solo is dead, until their force connections.
Ben uses Rey as his focal point, it consumes him almost how much he focusses on her. In TLJ especially, he's listening intently to her when she cries, or even insults him, but he's focussing all of his attention on her to let her know she isn't alone. He knows how it feels afterall.
Rey is the only one who gets to see Kylo stripped down to the scared, seemingly kind and gentle Ben in their connections. She realises she can save him, she has to because now she loves him too. This is her goal, she uses him as a focal point so she doesn't lose sight of her goal and future.
They both move far together, battling their own personal demons and Ben is the one to nurture and care for her and watch her bloom into the young Jedi she is, even if it should be Luke. They both delve deeper into their emotions, finding that love.
Then the hand touch. Ben uses her as a makeshift gauge of how much he can give to her, and how much he should take back. Rey does the same, she hasn't ever dabbled in the subject of romance and relationships, but she needs to touch his hand and she knows he needs it too.
They both found love exactly where it wasn't supposed to be, in the form of their enemy. The minute the hut blows apart via Luke, Ben's face contorts into panic and he continues to hold out his hand for her as if he needs her for comfort.
Rey of course goes on board the ship to see Ben, to bring him home to her as she misses him more than she thought she would. Luke isn't talking sense to her, so she needs Ben to.
Ben looks at her like she holds the moon and the stars, like she's everything in the galaxy and there's nothing else. He's found the love he never had, or never knew he needed, and it's driving him insane. He needs Rey to talk sense into him. As soon as she arrives, he's relieved and relaxed after having missed her and needed her.
In the throne room, when they fight for each other, Ben and Rey are constantly checking up on each other and focusing on the other's safety. They work together, even if they aren't meant to be in love.
Ben stops fighting momentarily, he needs to see if she's ok. As soon as he sees that she's hurt, he's furious and even that shows how far he's come: going from only caring about being the next Vader, to caring about the girl he loves with an unguarded passion.
And then comes the moment in which Ben realises just how much he needs her in his life. His focal point is blurred now, but he knows it's her. Rey still needs him, but she can't go to the first order and let Ben abandon who he is in his heart. His love is right there in front of him, where it shouldn't be.
Ben knows how important this is. He knows what's at stake here, his heart. Rey knows too, hence why she begs and pleads for him to come back to her and be the man that she loves; Ben Solo.
Both are heartbroken when they need to fight, they can't bear to hurt each other again but they know they need to. The lightsaber may represent their broken hearts, and that Rey holds hers and Ben's in her hands.
And then they see each other again before she boards the Falcon fully.
He's shocked, surprised, astounded that she's still there. Rey looks back at him with the same emotions whirring through her head.
They missed each other more than they thought they would, and are relieved to see each other alive.
*TROS SPOILERS AHEAD*
After all of the torment of his forbidden, but requited, love Ben decides that's enough. He turns back for her, he goes home to the light for his focal point which he has finally achieved. Rey has achieved her focal point too, to save Ben Solo. To them, no one else is talking sense; but they are to each other.
And then when she dies, Ben knows it was right to use her as a warning sign. His heart was broken again, he couldn't lose her.
He brings her back using his own energy (or if you're like me and refuse to accept that he's dead and he used Leia's enenergy instead) and he uses it as a knew focus to bring her home to him.
The minute she wakes up he knows even if their love was never meant to be, not where it was supposed to be, that it's real.
They found love where it wasn't supposed to be, right in front of them.
