Conversation so far:
What happened in Doris Duke's personal life?
Doris Duke reportedly had numerous affairs.
When did Doris Duke have an affair?
In 1944 Cunningham-Reid married Angela Williams. During the Second World War he conducted an affair with the American heiress Doris Duke.
What else is notable about Doris Duke's personal life?
Doris Duke married twice.
Who was Doris Duke married to?
Doris Duke married twice, the first time in 1935 to James H. R. Cromwell.
Who was Doris Duke's second marriage with?
On September 1, 1947, while in Paris, Doris Duke became the wife of Porfirio Rubirosa.

Question: How long were they married?
Self-contained rewrite: How long were Doris Duke and Porfirio Rubirosa married?