Catherine, the only human being that Heathcliff loved and never physically attacked, or even restrained and oppressed. She was self-centered, spoiled, outspoken and lacked empathy, but she was the only one who loved Heathcliff. They were the same except for their gender, both ready to explode with passion and violence at the smallest provocation. No wonder Catherine died so young, what with all that fiery drama wearing out her heart.
It's ironic that Heathcliff was such a misanthrope that he wanted to kill everyone in the novel at one time or another; however, the only person that he loved died first. Mr. Earnshaw died early on in the novel but Heathcliff didn't love him the way he loved Catherine. Even Catherine rejecting him to marry Edgar Linton to improve her social status and living conditions didn't cause Heathcliff to harm her. Instead he sought vengeance on Hindley for reducing him to the status of a yard boy. Then he sought vengeance on Linton for wooing Catherine away from him.
Catherine, unlike so many young women, knew that committing to a life with a dark brooding bad boy, would be a difficult penniless future. So many women fall for the hot bad boy believing that after they get married or after they have a baby, he'll suddenly become a loving provider. But all they get is a punch in the face for being a nag.Then he'll say it was her fault that he hit her. Of course, every girl wants to think that they're the only one special enough to make the bad boy turn good with their special brand of love, but it doesn't happen in real life.
Love can work wonders, but it isn't magic, although it can seem magical at times. Catherine died of a broken heart of her own making while blaming it on Healthcliff and Edgar. Her emotional pain was worsened by regret that both men couldn't get along so she could have the best of both of them. She expected them to accommodate her bad decision in marrying Edgar like the self-involved adolescent that she was. Fortunately, they got it all straightened out in the afterlife.