Forbidden Office Daddy by Carmen Falcone

After breaking up with his longtime girlfriend, Nate Collier dives into work, but his carefully crafted life gets disrupted when his loyal assistant comes back from vacation with a new look—a new, irresistible look and a sexy attitude that make him feel sinfully tempted, even though he knows he can’t have her. Why? Because he can’t date his employees and break his own rule. Besides, she’s way younger and he doesn’t want that kind of trouble.
Manuela Gomes always had a crush on her hot boss. When he breaks up with his girlfriend, she takes the opportunity to reinvent herself—in more ways than one. She goes through a makeover, but also decides to show him that she’s a contender for his now-available heart. She’ll make him see she’s been under his nose all along—and she’s more than ready to be under his body, on top of him, and anywhere else he’ll have her.