Oh man, I totally loved Nina/Tomas in "Black Swan". Mostly 'cause the squicky power issues make it disturbingly hot, but I also just loved that final kiss after she's "won". It was kind of weirdly sweet.

There's also Kara/Leoben, and Damon/Katherine, and Wesley/Faith. And oh, Tom Riddle/Ginny Weasley. All of which include a history of abuse and questionable consent issues. Yep.