Night Swim by Jessica Keener

"Sixteen-year-old Sarah Kunitz lives in a posh, suburban world of 1970 Boston. From the outside, her parents' lifestyle appears enviable - a world defined by cocktail parties, expensive cars, and live-in maids to care for their children - but inside their five-bedroom house, all is not well for the Kunitz family. Coming home from school, Sarah finds her well-dressed, pill-popping mother lying disheveled on their living room couch. At night, to escape their parents' arguments, Sarah and her oldest brother, Peter, find solace in music, while her two younger brothers retreat to their rooms and imaginary lives. Any vestige of decorum and stability drains away when tragedy hits one terrible winter day. Soon after, their father, a self-absorbed, bombastic professor begins an affair with a younger colleague. Sarah, aggrieved, dives into two summer romances that lead to unforeseen consequences. In a story that will make you laugh and cry, Night Swim shows how a family, bound by heartache, learns to love again."