On the Rocks (Swizzle Stick Romances 2) by Georgia Beers

Vanessa Martini has strict dating rules and no patience for messy lives, which is why Grace Chapman should be an automatic no. Grace is juggling a divorce, a demanding boss, and parents who never stop judging her, and all she cares about is helping her son Oliver through the upheaval. Vanessa, Oliver’s teacher, sees Grace as one more complication she refuses to invite into her life. Grace sees Vanessa as another person who disapproves of her. They are certain they will never fall in love, even as every rule and every assumption begins to crack.