In 1770, at the age of thirteen, Lady Louisa fell in love with her second cousin, William Medows (1738–1813), the son of Philip Medows of Nottinghamshire, Deputy Ranger of Richmond Park, and of Lady Frances Pierrepont, who like Louisa's mother was a granddaughter of Evelyn Pierrepont, 1st Duke of Kingston-upon-Hull. Medows was then a forty-one-year-old lieutenant-colonel of the 5th Regiment of Foot, and Lord Bute considered him unsuitable and put a stop to it. Lady Louisa was bitterly disappointed. She wrote of Medows:
“He seems to have that independent spirit which fortune cannot depress or exalt. He is really a character unlike anything but himself, au reste, the most agreeable man I ever met with, and one of the most humorous.”
Later the same year, Medows married another lady, Frances Augusta Hammerton, and went on to become a Lieutenant-General, a Knight of the Bath, and Governor-General of Madras.