M.M. Scrooge by Lee Colgin

Marley Jacobs is dead, and Max Masters Scrooge has no time for the sob story of the grieving son. Even if Jacobs Jr. is kinda cute—for a nerd.
Daniel Jacobs is anxious, drifting, and lonely. His gut tells him he’s overdue for a dose of self-care, but the thought of setting foot in a gym gives him hives. Though he craves gentle guidance, what he gets is the heavy hand of the gym’s head trainer and sleaziest playboy, Max Masters.
Accustomed to topping the leaderboard, among other things, Max sells Daniel on his gold package. After things get steamy in the locker room showers, Max is ready to make like a ghost and vanish, as usual. But this time, he won’t get away with his selfish antics, not if a vengeful past hookup with a powerful uncle has anything to say about it.