Forces of Nature by Elle Rivers

Ruth Murray thought she had seen the last of Knox Price when she walked away from him at their high school graduation.

After always coming in second place, she was ready to be done with their rivalry and make something of herself.
But then he went on to create PATH, a company that retrofitted cars to self-drive, cutting automobile accidents in half. His name was in everyone’s mouths, especially her parents, who still compare her to him even ten years later. His success is a sore reminder of her own stagnant career.
When he mysteriously steps down as CEO of his company, she hopes this will be the reason he finally disappears from everyone’s minds.
Until she walks into work and sees Knox is the newest executive of her company and, technically, her boss. All she can hope is that he doesn’t remember their little rivalry, because he now has the power to make her life a living hell.

Knox Price should be on top of the world.

He’s created an invention that saves lives, made his parents proud, shares his company with his best friend, and has more money than he knows what to do with.
And yet, he feels nothing.
He’s a robot, pretending to be human but never actually feeling a thing. It’s taken over his life, so much so, that his best friend suggests for him to step down and find passion in helping a different business build something great. When he returns to his hometown, he’s content to spend extra time with his parents and work on a new app for a company he doesn’t own.
That’s when he sees the woman he could never forget.
Ruth Murray is as feisty and hardheaded as ever, and instead of feeling the emptiness he’s grown used to, his heart starts beating again from the very moment he sees her.
The only problem? She hates him and he doesn’t know why.
With the media clawing to get more information about him, and a ruthless boss out to fire Ruth for any reason, he should stay away from her. But the longer he’s around her, the more he realizes he can’t keep his distance.