Lady Elizabeth married Philip Stanhope, Earl of Chesterfield some time before 25 September 1660. He was one of the lovers of the notorious Barbara Villiers, mistress of King Charles II of England. There were many at court who believed Barbara's first child, Anne bore a strong resemblance to Chesterfield. His first wife was Lady Anne Percy, daughter of Algernon Percy, 10th Earl of Northumberland; she died on 29 November 1654 with no surviving children.
Together Elizabeth and Chesterfield had one daughter, Lady Elizabeth Stanhope, later Countess of Strathmore, although the child's paternity was in doubt. According to Samuel Pepys, theirs was a marriage of convenience, but Chesterfield, despite his own past conduct with Barbara Villiers, became jealous when rumours spread that his wife was having affairs with both James Hamilton and James, Duke of York, with whom she is said to have been caught in flagrante delicto. On the other hand, he describes Elizabeth as "a virtuous lady".
The Chevalier de Grammont, in his memoirs, says of Elizabeth that, "she had a most exquisite shape, though she was not very tall: her complexion was extremely fair, with all the expressive charms of a brunette: she had large blue eyes, very tempting and alluring: her manners were engaging: her wit lively and amusing; but her heart, ever open to tender sentiments, was neither scrupulous in point of constancy, nor nice in point of sincerity."
In May 1663, the couple went to live at Bretby in Derbyshire. It was around this time that their daughter, Elizabeth was born.