Ron/Draco.
Ron Weasley hated Slytherins. They were sneaky, manipulative and down right creepy sometimes.
Even more than Slytherins in general, Ron Weasley hated the Malfoy's. Slytherin as they came, not to mention rich, snobby and rude. The Malfoy's represented everything that Ron saw wrong with the wizarding world; prejudice, cruel and disdaining of new development. And they had all been Slytherin's for generations, which seemed to scream terrible things to Ron's logic.
Up until today, the only thing he had hated more than the Malfoy's in general was Draco Malfoy. Draco Malfoy was spoilt, rude, derogatory and a down-right foul sort of person. Ron had watched Draco sneak around breaking rules and getting away with it, being horrible to people who don't deserve it, drive people into rages with a sentence and then sneer in the face of their despair.
Yes, Draco Malfoy had shown all the traits of someone that Ron wouldn't like. Ever.
Somehow, it had come to a point where they were hiding in broom closets as the blonde surrendered under the domineering kisses of the tall keeper.
It had started after the war, when Draco was looking so lost and confused. Grey eyes filled with despair as he father was sentenced to Azkaban and his mother to house arrest, wandering the halls of Hogwarts for his final year with no friends, no family and seemingly no future.
Ron had yearned to make him feel something positive- anything positive- and once he had gotten that first taste, he had kept coming back for more, and more.
It was not something he could help, but Draco Malfoy had become an obsession to him, and he couldn't stop. Draco Malfoy was his drug, and he just kept drowning to keep that lost look off the pale face of his once rival.