Conversations with Friends by Sally Rooney

Frances is twenty-one years old, cool-headed and observant. At night she performs spoken word with her best friend Bobbi, who used to be her girlfriend. When they are befriended by Melissa, a well-known journalist who is married to Nick, an actor, they enter a world of beautiful houses, raucous dinner parties and holidays in Provence, beginning a complex ménage-à-quatre. But when Frances and Nick get unexpectedly closer, Frances is forced to honestly confront her own vulnerabilities for the first time.