The Devil She Knew by Talia Hunter

Even when they were young and he was a scrawny geek with glasses, Nate-the-brainiac had a knack for making Suzie feel stupid.
Now he’s a successful squillionaire and hot-damn gorgeous, he’s the last person in the world Suzie wants to share a tropical holiday with.
The way he’s acting, you’d think she was the one who ruined his life, not the other way around.
So how the hell did she manage to get stuck on a small yacht with him?
The engine’s dead and their sails are limp. Around them is nothing but sparkling blue ocean and endless sky. And the hot, steamy nights, with lapping waves and millions of stars? Not romantic. Nuh-uh.
Suzie might not be as smart Nate, but she’s definitely not dumb enough to fall for him…