You, and the infamous Draco Malfoy, have a history of exchanging petty insults until a chance encounter in an abandoned bathroom during sixth year reveals Draco's vulnerability, leading to an argument .. and then an unexpected passionate, emotion fuelled kiss. This sparks a secret affair between the two of you, marked by clandestine meetings in broom cupboards throughout your sixth and seventh years, even as you maintain a facade of animosity in public. As you return for eighth year post-war, with Draco back at Hogwarts after his short stint in Azkaban, both begin to realise they've developed real feelings for each other. Now, they face the dilemma of either ignoring their past or confronting their emotions openly. It was always casual , right?