The Duchess of Argyll's sex scandal caused quite an uproar in British High Society when it first came to light in 1963 and her daughter-in-law had recently opened up about the socialite's mystery man who had been kept a secret for the past 50 years.

The other half of the Duchess of Argyll's sex scandal was an American airline exeutive, a suave and sensual individual, according to the duchess' daughter-in law. 

Margaret Campbell, also known as the Duchess of Argyll, divorced her husband in 1963 after photos of her and a mystery man performing sexual acts ermerged in court. The man's identity remained unclear since his head had been cut out of the pictures.

The Duchess of Argyll's mystery  man was finally identified as William "Bill" Lyons who then served as Pan American World Airways' sales director, confirmed the duchess' daughter-in-law.

"For 50 years it has been safely, maybe too safely, kept - for in keeping it, we have also perpetuated the mystery, and in so doing we have done Margaret's reputation no favors," Lady Colin Campbell, the Duchess of Argyll's daughter-in-law, shared to The Daily Mail. 

Lady Campbell confirmed that the Duchess of Argyll herself confided in her that her secret lover was Lyons.

According to Lady Campbell, her mother-in-law described Lyons as "sophisticated, debonair, dapper, well-bred, charming and handsome." She added that the Duchess of Argyll also described Lyons as sexy, reliable, astute and great fun, much like Charlie, her first husband. 

Lady Campbell also shared that those who had been close to the Duchess of Argyll had not been surprised with the identity of her mystery man, confirming that it was natural indeed since Bill had been the duchess' lover.

The Duchess of Argyll's first husband had also reportedly gotten hold of her diary which contained the names of several men. During the divorce proceedings, the Duke claimed that his wife had cheated on him several times with different men. 

The Duchess of Argyll had denied these allegations however, saying that the names on the diary were only homosexual friends. She did not disclose any further information on these men's identities since homosexuality had been a crime in Britain back in the 1960s.

The Duchess of Argyll passed away at the age of 80 in 1993.