https://en.wikipedia.org/wiki/Lady_Cynthia_Mosley

Lady Cynthia Blanche Mosley (23 August 1898 – 16 May 1933), nicknamed "Cimmie", was a British politician of Anglo-American parentage and the first wife of the British Fascist and New Party politician Sir Oswald Mosley, who was formerly a Member of Parliament in both the Conservative and Labour parties.

Childhood

Born Cynthia Blanche Curzon at Kedleston Hall, she was the second daughter of Hon. George Curzon (later Marquess Curzon of Kedleston) and his first wife, Mary Victoria Leiter, an American department-store heiress. As the daughter of an Earl (and later a Marquess), she was styled Lady Cynthia beginning in 1911.

Marriage, family and politics

On 11 May 1920, Cynthia married the then-Conservative politician, Oswald Mosley. He was her first and only lover.

Children

They had three children:

Vivien Elizabeth Mosley (25 February 1921 – 26 August 2002), who on 15 January 1949 married Desmond Francis Forbes Adam (1926-1958) who was killed in a car crash nine years later; and had issue.

Nicholas Mosley, 3rd Baron Ravensdale (25 June 1923 – 28 February 2017), a successful novelist who wrote a biography of his father and edited his memoirs for publication; and had issue.

Michael Mosley (born 25 April 1932), died unmarried and without issue.

Political life

After both joined the Labour Party in 1924, she was elected Labour Member of Parliament (MP) for Stoke-on-Trent in 1929, her husband having been elected MP for Smethwick in 1926. Frustrated with the ruling Labour Party's complacent and conservative response to high levels of unemployment, Oswald Mosley formed the New Party on 1 March 1931 which his wife also joined. The party failed to win any seats at the 1931 general election. After that Mosley started his move towards fascist policies, losing many of those who had joined the New Party as a result.

Husband's adultery

During their marriage her younger sister Lady Alexandra was a mistress of Mosley, as was, briefly, their stepmother, Grace Curzon, Marchioness Curzon of Kedleston.

Electoral defeat and death

All the New Party's candidates in the 1931 election lost their seat or failed to win in constituencies, instead seeing a unified coalition government which involved the Conservatives, Liberals and a breakaway from the main Labour Party amid the Great Depression. Cynthia Mosley herself did not stand in the election. From then on she drifted away from her husband politically, having no sympathy for his move towards fascism. She died in 1933 at 34 after an operation for peritonitis following acute appendicitis, in London.