Complex sentence: Whitney was born Kenyon Fortescue in 1914, but was known as Helene, and became Helene Fortescue Reynolds on marrying Julian Louis Reynolds, an heir to the Reynolds aluminum and tobacco fortunes, in 1936, who she divorced in May 1939.
Split into simpler sentences: Whitney was born Kenyon Fortescue in 1914, but was known as Helene. She married Julian Louis Reynolds, an heir to the Reynolds aluminum and tobacco fortunes, in 1936, becoming Helene Fortescue Reynolds in 1936 and was divorced in May 1939.