Answer:
The most obvious is the love/hate relationship between Catherine and Heathcliff. He is abusive towards her and yet at the same time loves her very much. Catherine never marries Heathcliff but in doing so leads a life of depression and eventual death. Heathcliff is referred to as a "devil" but only because his charm is so two-faced.
One could also see that Wuthering Heights itself is a Love/Hate estate. While the manor is large and the landscape sublime, the house can also be seen as an analogy for Hell. Catherine is seen describing Heaven as a place she would be most unhappy but at Wurthering Heights she is at peace. She hates its dark gothic walls but could be happy no place else.