Modern Lovers by Emma Straub
Twenty years later and they were supposed to be grown-ups... Ditmas Park, Brooklyn. College friends Elizabeth, Zoe and Andrew had a band, grew up, settled in New York and now they are still living round the corner from one another (and in each other's pockets).
One hot summer as their kids come of age, making those first hesitant steps into adulthood, it's the parents who find that the lives they've so carefully stitched together begin to slowly unravel . . .