In 1953, Lee married Michael Temple Canfield, the adopted son of Cass Canfield, chairman of the publisher Harper & Brothers. They lived in London, where Mr. Canfield was private secretary to Winthrop Aldrich, the United States ambassador to the Court of St. James’s. They had no children and were divorced in 1958. The marriage was later annulled by the Catholic Church.
In 1959, she married Prince Radziwill, 20 years her senior, who had arrived in London in 1946 and made a fortune in real estate. The couple had an estate near Henley-on-Thames and a Georgian townhouse near Buckingham Palace. They had two children, Prince Anthony and Princess Anna Christina, and were divorced in 1974. Anthony died in 1999.
In 1988, Mrs. Radziwill married Herbert Ross, the director and choreographer, whose films included “The Sunshine Boys” (1975), “The Goodbye Girl” (1977) and “Steel Magnolias” (1989). They were divorced shortly before his death in 2001, and she resumed the Radziwill surname. In addition to her daughter, Anna Christina, Mrs. Radziwill is survived by a daughter-in-law, the actress Carole Radziwill, and her half-brother, Jamie Auchincloss. Her half-sister, Janet Auchincloss, died in 1985.
Mrs. Radziwill was a public relations executive for Giorgio Armani from 1986 to 1994, directing special events for the Italian fashion designer.
After Mrs. Onassis died in 1994, her will made no material provision for her sister, “for whom I have great affection,” Mrs. Onassis wrote, “because I have already done so in my lifetime.” It left bequests to each of her sister’s children. The disinheritance of Mrs. Radziwill was widely interpreted as another sign of strain between the sisters, whose relationship had captivated the press and public throughout their lives.