In chapter 9, Catherine confides to Nelly that Edgar has proposed to her. She is concerned about it and wants to know if Nelly thinks she should marry him. In the course of Nelly questioning her, Catherine reveals that she wishes to marry Edgar for a series of shallow reasons: he is rich, he is handsome, he loves her, and he offers her an escape from the dysfunctional family life she now endures. Nelly says these are poor reasons to marry someone. Catherine then confesses she loves Heathcliff but says that he is too degraded for her to marry now.
Heathcliff has been listening, unbeknownst to Catherine, but now he slips away. Therefore, he misses Cathy telling Nelly how deeply she loves him. She says to Nelly,
My love for Linton is like the foliage in the woods: time will change it, I'm well aware, as winter changes the trees. My love for Heathcliff resembles the eternal rocks beneath: a source of little visible delight, but necessary. Nelly, I am Heathcliff!
Catherine goes on to reveal that her thoughts are always with Heathcliff. He is a part of her. She says they can never, for that reason, be separated. She also confides that part of her plan in marrying Edgar is to help Heathcliff rise in the world. She expects Edgar to welcome him into their married life, because she can't bear for it to be otherwise. Nelly warns her that Edgar might have different ideas, but Catherine refuses to hear this.