The First Circle - Devil In The Waters, #1

All through high school, Devlin Stone made Josh Waters' life miserable in the way only a true bully can. Ten years later, Josh wakes on a groggy morning after his and his wife Kimmy's high school reunion. There'd been a lakeside rager at the cottage of Dalton High's most popular girl, and maybe he'd indulged a little too much. What happened last night, anyway? . . .  Devlin Stone's there to tell him.
"I did what you wanted, Josh." What did Josh want? Not that, there was no way in hell he asked for that . . .  Devlin says You did, Josh, and now it's done. I slept with your wife-and I'm going to keep doing it. Kimmy's too much woman for you, and you just made a deal with the devil . . .