As close to us as breathing : a novel / Elizabeth Poliner.

Enhanced descriptions from Syndetics:

A multigenerational family saga about the long-lasting reverberations of one tragic summer by "a wonderful talent [who] should be read widely" (Edward P. Jones).

In 1948, a small stretch of the Woodmont, Connecticut shoreline, affectionately named "Bagel Beach," has long been a summer destination for Jewish families. Here sisters Ada, Vivie, and Bec assemble at their beloved family cottage, with children in tow and weekend-only husbands who arrive each Friday in time for the Sabbath meal.

During the weekdays, freedom reigns. Ada, the family beauty, relaxes and grows more playful, unimpeded by her rule-driven, religious husband. Vivie, once terribly wronged by her sister, is now the family diplomat and an increasingly inventive chef. Unmarried Bec finds herself forced to choose between the family-centric life she's always known and a passion-filled life with the married man with whom she's had a secret years-long affair.

But when a terrible accident occurs on the sisters' watch, a summer of hope and self-discovery transforms into a lifetime of atonement and loss for members of this close-knit clan. Seen through the eyes of Molly, who was twelve years old when she witnessed the accident, this is the story of a tragedy and its aftermath, of expanding lives painfully collapsed. Can Molly, decades after the event, draw from her aunt Bec's hard-won wisdom and free herself from the burden that destroyed so many others?

Elizabeth Poliner is a masterful storyteller, a brilliant observer of human nature, and in As Close to Us as Breathing she has created an unforgettable meditation on grief, guilt, and the boundaries of identity and love.