In 1811, Quentin married Georgiana (died 1853), the youngest daughter of James Lawrell of Eastwick Park, and of Frimley Park, Surrey. She was reputedly unfaithful to her husband, and became celebrated as a royal mistress, under the names "Mrs Quentin" or "Harriet Quentin" (a misnomer). In 1822, a pamphlet appeared, Memoirs of the Celebrated Mrs Q—– by "Edward Eglantine", a pseudonym of William Benbow. It was reprinted in 1906 in Mrs Q—— and "Windsor Castle", with plates, by the collector Joseph Grego.
