Burning for the Nanny by Suzanne Jenkins

Roberta and Big Mike Saint’s fourth son, Leonardo, or Leon, is a player. Following in the footsteps of his namesake grandfather, father, uncle and brothers he graduates from the fire academy and is hired at Station #34 where he begins his career as a firefighter.
But during his first week on the job, a surprise visitor, someone he barely remembers from a one-night stand, shows up on his parents’ doorstep with demands he’s not prepared to make, including the possibility that he could jeopardize his position at the firehouse.
Then Ava, a beautiful neighbor with a reputation comes to the rescue. Will Roberta and Big Mike’s animosity toward Ava be enough to discourage Leon from succumbing to her charms? Or will his need for her force him to grow up, once and for all?