Roger Moore and her lack of confidence in his acting ability took their toll on the relationship, during which he allegedly suffered domestic abuse. In 1952, Moore met the Welsh singer Dorothy Squires, who was 12 years his senior, and Van Steyn and Moore divorced the following year. Squires and Moore were married in New York. They lived in Bexley, Kent, after their marriage. They moved to the United States in 1954 to develop their careers, but tension developed in their marriage due to their age difference and Moore's infatuation with starlet Dorothy Provine, and they moved back to the United Kingdom
Marcia Moore married four times throughout her life. Her first husband was Simons Roof, with whom she had three children, Louisa (Loulie) in 1948, Christopher in 1951, and Jonathan (Jonny) in 1953. The couple divorced in 1961, and she married Louis S. Acker in 1962. She later married Mark Douglas and moved to Maine, where the couple published a series of books on yoga. In the late 1970s, she married Howard Alltounian, M.D. (1937-2006) and they moved to Washington, near Seattle. Moore's personal papers, the Marcia S. Moore Collection, 1948-1999 (Bulk 1948-1964), were given to Concord Library by her son Christopher Roof