The White Rose — Jean Hanff Korelitz

Passion, infidelity, social climbing, and one very special white rose weave a seductive narrative in this intelligent and tender novel.
At forty-eight, Marian Kahn, a professor of history at Columbia, has reached a comfortable perch. Married, wealthy, and the famed discoverer of that eighteenth-century adventuress, Lady Charlotte Wilcox, she ought to be content. Instead, she is horrified to find herself profoundly in love with twenty-six-year-old Oliver, the son of her oldest friend. When Marian's cousin, the snobbish Barton, announces his engagement to Sophie, a graduate student in Marian's department, Marian, Oliver and Sophie find their affairs woefully entangled, and their hearts turned in unfamiliar directions. All three of them will learn that love may seldom be straightforward, but it's always a gift.
From the West Village to the Upper East Side, from the Hamptons to Millbrook, The White Rose is at once a nuanced and affectionate reimagining of Strauss' beloved opera, Der Rosenkavalier, and a mesmerizing novel of our own time and place.