Eleanor de Warenne had a crush on her step-brother Sean, from the time their parents married when she was a very young child. Eleanor helped Sean rebuild his ancestral home, dresses in men's breeches to ride horses, and tells whichever brother is currently doing her a favor that he is her very favorite brother. After Sean leaves home and doesn't return for four years, Eleanor finally agrees to marry a very wealthy British lord, though she doesn't love him, because she's still got this kind of sick thing for her step-brother.
Sean O'Neil was always a good sport about tolerating Eleanor's spying, hero worship, and rescuing her when she got into trouble. In the four years he's been away, he married, lost his wife and step-son under very tragic circumstances (and of course he blames himself) and spent two years in isolation in a British prison. He's a very anguished criminal on the run. Sean shows up on the eve of Eleanor's wedding and all kinds of madness takes place. These two are some ridiculously tortured lovers.
As much as I enjoy these silly romance novels, I would never survive as a character. I'd be all "Sorry, I can't handle this star-crossed shit. I'm just gonna marry the rich guy." See? I wouldn't even have the vernacular down.