The ending of Wuthering Heights is bittersweet. Heathcliff, realizing that all he wants is to be with Catherine, stops caring for himself. While his death was not directly a suicide, it could be argued that it was nevertheless self-inflicted, since he had stopped eating.
When Lockwood returns to Wuthering Heights, he is surprised to learn of Heathcliff's death. He gets another surprise when he learns that Cathy and Hareton are in love and planning to marry. Heathcliff's death, tragic as it may seem, leaves the next generations of the Earnshaw and Linton families free to live their lives in peace. Hareton and Cathy inherit both Thrushcross Grange and Wuthering Heights and plan to marry on New Year's Day.
It also seems that while not fated to be together in life, death has finally brought Heathcliff and Catherine together. When Lockwood goes to look at the graves of Catherine, Heathcliff, and Edgar, he feels sure that they are all at peace. In addition, in the aftermath of Heathcliff's death, several villagers report sightings of Heathcliff and Catherine's ghosts wandering around the moors. Given how complicated their situation in life was, it could be argued that since they were fated to be together, they find peace and contentment in the afterlife.