For many this epitomises a love story, as love really is. One may decide to be prudent, to marry well and suitably, but when your heart is given it will not follow the diktats of mind and society, however much one reigns it in. Short of raising consciousness and rising above there might not be a way out.
Cathy and Heathcliff epitomise tortured love that cannot let go and will not let social structure or healthy relations dictate heart. They seem to be bound by more than heart, by life itself in one being linked to that in another.
Willful Cathy married another, a decent person, since marrying a poor servant was out of the question in feudal society; and there began the tragic epic tale that could only return to life after ruining several lives, through her strong daughter of the same name.