When he was young, before Hogwarts, he used to think his parents were in love. He wasn't entirely sure what that meant, but he knew it was something that parents were supposed to be. He remembers arguments, essentially the only times his parents spoke to one another, during which his mother would say things like, "I can't believe you're doing this, Lucius," and, "can't you just think about us for once?" and his father would invariably reply, "I have a pledge." Things went quiet after that, and Draco would tiptoe to his room past his father's study, not wanting to get caught. He could always hear his mother wailing disconsolately from some remote room in the manor, and he wondered at the projection. The next morning, he would hear her muttering fervently, "I hate this place," to whomever would listen. 'Whomever' seldom included his father.
This is love, to Draco.
And this is why Harry makes sense, because they have all the makings of what love should be. The tension, the arguments, the friction, the underlying hatred. The only part that's wrong is that Draco doesn't go out of his way to avoid Harry, but rather goes out of his way to run into him. And he tries, he really tries to get Harry to talk to him civilly, without either of them raising their voices or their wands, and he thinks that maybe this isn't love after all. Love is supposed to be some sort of battle, and this is just too easy.