The Last Nanny In Manhattan by K. Sterling

Walker Cameron III might be one of the most feared men in Manhattan, but he’s no match for his six-year-old triplets. After exhausting all other options, Finley Marshall is the grumpy widower’s last hope.
Luckily for the Camerons, Fin is a master of chaos and can calm even the most beastly of children. But Fin soon learns that the girls aren’t the problem; it’s their father. Still grieving and easily overwhelmed, Walker leaves the servants to cope with his little hellions. Fin wants to prove he’s the best nanny in the city and that his older brother, Reid, should start his own agency. Is Fin willing to risk life and limb to do it, though?
Afraid to lose the most competent caregiver to ever cross his threshold, Walker agrees to an unusual set of terms. He’ll give the girls more of his time and practice better parenting with Fin as his guide. But Walker finds himself with a new and unexpected problem. For the first time in years, he’s having very improper thoughts and can’t stop thinking about Fin. Can he keep his feelings to himself or will Walker fall for the last nanny in Manhattan willing to take on the cursed Camerons?