Okay but one of the things *I* love about Rosaline and Jacob is that there's zero sex to the relationship. There's attraction, and it ends with a kiss. But no sex (unless we get hopeful about a quickie in the backseat.)
When we meet Rosaline, her relationships with men seem to be in a realm of distant, inappropriate and sex-driven. She's have a clandestine relationship with a much younger, married co-worker with the emotional maturity of a toothpick. It's surface-level to the point where sex is almost in opposition to vulnerability. And it's part of a pattern: Rosaline has a history of sleeping with married men. She is a consummate singleton.
With Jacob, not only is he not like Nick at all. But we have opportunities for sex that are rejected. He offers her a pint, but she dismisses it. Rosaline seeks him out, stays at his place... but he sleeps on the sofa. She's in her underwear and vest with him... but to swim.
She doesn't fall into that pattern with him of using him as an outlet or disposable or something to make her forget or punish herself or whatever meaningless sex means to her.
So he manages to get closer, listen to her, have her be vulnerable with him and open. He sees her naked without seeing her naked.
I think what’s so beautiful about their dynamic is how unlikely it all is. Dean himself has described their relationship as a “right place, right time” sort of thing and as different as they are as people, they feel right for each other.
Jacob softened Rosaline in ways that even she didn’t think was possible. He didn’t expect anything in return either, which is another way he differs from all the other dudes Rosaline is used to associating with. And even though he clearly was attracted to her, he never pushed for more because she was just looking for a familiar face, a friend. Yes, he did kiss her first… but Rosaline was the one pressed her entire body against him, so he probably took cues from her body language.
And I think Rosaline saw Jacob as “safe”, you know? He was also one of the first people in the show to see right through her tough exterior, and not once did he judge her. He also just took care of her during their stay on the Isle, but it was a different sort of care than the kind Becca used to offer. It’s also probably the first time in a long time a man looked at her without wanting sex or a professional connection.
For two people who’ve known each other for at most a week, their relationship is already so deeply personal.