The son of John and Sophia Catherine Musters, the younger John took the surname of Chaworth, but later resumed the Musters patronymic. In 1805, he married Mary Ann Chaworth [d. 1832], only daughter and heir of George Chaworth of Annesley, Nottinghamshire. The couple had four sons and four daughters (one daughter died young). Of Musters and his wife, Thormandy writes: "He married Mary Anne, the only daughter of George Chaworth of Annesley, and heiress to a great estate which bordered upon that of the Musters. Miss Chaworth was as beautiful as she was wealthy, and a romantic interest attaches to her name from the fact that she was the object of Lord Byron's early and passionate love....Mary Chaworth, however, had given her heart to handsome Jack Musters, who was as fine a specimen of a manly athletic young Englishman as any woman could wish to see, an accomplished dancer, gifted with a fine singing voice, and pronounced by the Prince Regent himself to be 'the most perfect gentleman he ever met...' [Their] marriage was not [however] a happy one. Handsome Jack unfortunately had an ineradicable propensity to make love to every woman he met. His irregularities in this respect caused discord at home, which culminated in a separation from his wife, whose mind became subsequently affected to a degree which almost justified Byron's words [from his poem, The Dream], `the one to end in madness.' ...Musters became Squire of Annesly by his marriage to Miss Chaworth, and hunted his hounds there for several seasons... [He] was a clever and successful breeder of hunting hounds. In the drawing-room Jack Musters was distinguished for the refinement of his manner, and ladies always voted him `delightful'. But in the hunting-field he flung politeness to the winds, and the language in which he blew up `thrusters' who pressed too close upon his hounds was sultry to a degree, and sometimes passed the bounds allowed even to an angry Master of Foxhounds....But people forgave handsome Jack Musters these little failings, for, with all his faults, he was a fine, manly English sportsman, frank and generous, with a big heart encased in as magnificent a body as was ever given to man. And when he died at Annesley Park on the 8th of September 1849, in the 73rd year of his age, he left more mourning friends than many a better man has had to lament his loss."
Thormanby (pseud.). Kings of the hunting-field: memoirs and anecdotes of distinguished masters of hounds and other celebrities of the chase with histories of famous packs, and hunting traditions of great houses. London, 1899.
Townend, Peter, ed. Burke's Peerage Limited. Burke's Genealogical and Heraldic History of the Landed Gentry. 18th ed. 3 vols. London, 1969: 2: 463.