In twenty years : a novel / Allison Winn Scotch.

Enhanced descriptions from Syndetics:

Twenty years ago, six Penn students shared a house, naively certain that their friendships would endure--until the death of their ringleader and dear friend Bea splintered the group for good. Now, mostly estranged from one another, the remaining five reluctantly gather at that same house on the eve of what would have been Bea's fortieth birthday.

But along with the return of the friends come old grudges, unrequited feelings, and buried secrets. Catherine, the CEO of a domestic empire, and Owen, a stay-at-home dad, were picture-perfect college sweethearts--but now teeter on the brink of disaster. Lindy, a well-known musician, is pushing middle age in an industry that's all about youth and slowly self-destructing as she grapples with her own identity. Behind his smile, handsome plastic surgeon Colin harbors the heartbreaking truth about his own history with Bea. And Annie carefully curates her life on Instagram and Facebook, keeping up appearances so she doesn't have to face the truth about her own empty reality.

Reunited in the place where so many dreams began, and bolstered by the hope of healing, each of them is forced to confront the past.