The dazzle of wealth broadens her horizons, and her first taste of gentility results in the careless abandonment of her relationship with Heathcliff. The possibility of a future together for them in a world that required more prudent choices be made is despaired.
Her horizons are expanded by the opulence around her, and her first encounter with genteel society causes her to neglect her connection with Heathcliff. The chance of a shared future for them, given the need for wiser choices, seems unattainable.