The Match Un-Maker - Philippa Lodge

Genevra has debts, regrets, and a talent for finding the weak points in bad relationships.

Not that she's any good at figuring out her own relationships. Her ex lied to her and left her with the debts while taking their friend group with her.

Most of her interpersonal interactions happen during her paid gigs as a life coach with a magical talent for exploiting emotional fault lines to break poorly matched couples up.

Mostly, she uses her powers for good to try to save decent people from cheaters, beaters, and soul-eaters. Mostly.

When Florence, self-appointed matriarch of a huge, close-knit family, hires Gen to break up her great-niece's wedding an hour before it starts, Gen tries to fit in.

Worse: Florence hires her again to sort out other family members' love lives and Gen starts to make friends with her fake fourth cousins.

Worst: she falls for her fake cousin Sophia, the skeptic who can see Genevra's magical manipulations and wants her to stop.