How did Catherine marry Edgar? Where did Heathcliff go?
Catherine decides to marry Edgar Linton to escape Wuthering Heights. This is ironic, since it is the ultimate fate of her unquiet soul to roam those misty, muddy moors which brought Heathcliff and her so much joy as children, seeking to gain entry back into her childhood home. Just as Heathcliff found their proximity to the Linton children a kind of vague torture growing up, the reader discovers that Catherine did as well, however they were both tortured by the presence of these neighbor-children for different reasons. Heathcliff always despised them, and resented the influence they had on his Cathy. However, her response to Linton’s proposal reveals a long-held desire to be surrounded by nice, clean, expensive things and by mild, pleasant and civilized people, though she freely admits to Nelly that she is neither mild, pleasant nor civilized.
As much as Cathy is running away from her elder brothers feeble, drunken attempts at tyranny over her, from Heathcliff and her passion for him, she also wants a break from the overwhelming burden of being herself, and feels Linton might be just the thing to provide this much needed diversion. She tells Nelly of dream of being scorned by angels and kicked out of heaven, and how grateful she was not to be allowed in heaven, then admits:
“I've no more business to marry Edgar Linton than I have to be in heaven; and if the wicked man in there had not brought Heathcliff so low, I shouldn't have thought of it. It would degrade me to marry Heathcliff now; so he shall never know how I love him: and that, not because he's handsome, Nelly, but because he's more myself than I am. Whatever our souls are made of, his and mine are the same; and Linton's is as different as a moonbeam from lightning, or frost from fire.”
When Heathcliff hears this, he does run away from home for a time. He wants to prove Catherine wrong. Although he does come back to Wuthering Heights, wealthy and with a newly acquired-aristocratic bearing, he cannot be civilized because he is, at heart, a wild and unbroken thing. Nelly guesses he may have spent some time in the army, but Heathcliff neither confirms or denies how he’s made a lifetime of money in so few years, though the reader has to suspect something very underhanded, if not criminal, that required the thinnest veneer of propriety.