Key to My Heart by Brittany Cournoyer

Music, teaching, family.
For Maverick Wheeler, the only thing more important to him than his family is music. During the day, he’s a professor of Music Theory, and by night, he plays the piano in a jazz band. Between work and his father’s care, that doesn’t leave much time for a personal life. When fate keeps throwing the insufferable Christopher Bishop his way, Chris is the one to lend Maverick a helping hand when he needs one. And even though Maverick is starting to like Christopher the more time they spend together, Maverick knows he’s far too old for him.

Work, school, service.
If Christopher Bishop isn’t busy working at his family’s tow truck business, he’s filling his free time with visiting his grandfather or arguing with Maverick Wheeler. Sparks fly the first time they lay eyes on each other after a misunderstanding, and instead of fizzling out, they burn brighter with every encounter. After a fateful encounter, Christopher begins to realize the stuffy, yet tasty, professor isn’t such a bad guy after all. If only Christopher could convince him to get over their age difference.