Marriage, children and personal life
On January 27, 1908, she married Hungarian Count László Széchenyi (1879–1938) in New York City. Their union was the most talked about and widely reported since her cousin Consuelo Vanderbilt's. The couple visited Hungary almost every summer with their five daughters:
Countess Cornelia "Gilia" Széchényi de Sárvár-Felsövidék (1908–1958), who married Eugene Bowie Roberts (1898–1983), an heir of the Roberts family of Bowie, Maryland (a colonial family of Maryland), they had three children;
Countess Alice "Ai" Széchényi de Sárvár-Felsövidék (1911–1974), who married Hungarian Count Béla Hadik (1905–1971), they had two sons;
Countess Gladys Széchényi de Sárvár-Felsövidék (1913–1978), who married the half American English peer Christopher Guy Finch-Hatton, 15th Earl of Winchilsea (1911–1950), they had two sons;
Countess Sylvia Anita Gabriel Denise Irene Marie "Sylvie" Széchényi de Sárvár-Felsövidék (1918–1998), who married Hungarian Count Antal Szapáry von Muraszombath Széchysziget und Szapar (1905–1972), they had two children;
Countess Ferdinandine "Bubby" Széchényi de Sárvár-Felsövidék (1923–2016), who married Austrian Count Alexander von und zu Eltz (1911–1977), they had two sons.
In March 1912, Countess Széchenyi's jewelries worth $200,000 ($8 million today) was stolen from her town residence in Budapest, the detective afterward found the jewels in a motor car garage, where they had been hidden by being wrapped in a piece of newspaper behind a barrel. The countess promptly sent a $600 reward to the investigator. Upon learning of this, the Chief of Police issued an order for the money's return, stating that the police officer had fulfilled his duties and didn't need any further compensation.
Her sister Gertrude was married to Harry Payne Whitney, brother to Dorothy Payne Whitney, whose son Whitney Straight married Lord Winchilsea's sister, Lady Daphne Finch-Hatton.
In 1913, there were rumors that she was going to leave her husband due to his financial woes, including gambling away all of her dowry.
In 1951, she donated her mother's iconic Electric Light dress to the Museum of the City of New York.