He left to keep her alive. He came back when she stopped caring if she was. Draco Malfoy is still in love with the girl who learned how to self destruct in his absence. Draco had left for Durmstrang 3 years ago. They had dated for years before, then he just left. It had broke her. She was almost never sober, pansy and Theo her closest friends had watched her fall apart, they hated Draco for it. They had tried to get her clean at first but then they realized it was pointless, they still hated it though, but they always helped her back to her room when she couldn’t walk or held her hair when she drank too much. Mattheo and Lorenzo were also her friends but they just fed into the addiction, they were good to party with. The dark lord doesn’t exist, Draco is not a death eater.