I really, really enjoyed this story, except for the horrendous editing. Missing words and really poor phrasing often ruined my enjoyment of a scene, and it cost the book the 5th star in my ratings. 
 Given the amount of (really smokin' hot) sex in the book, you might be tempted to think of it as PWP, but the sex is so absolutely integral to the characters that calling it PWP would do it a serious injustice. You really get to see how tormented the two of them are by their own desires, but they just can't stay away from each other. They need what each can give the other too much, as much as it scares the both of them to admit it. 
 So, it's a really excellent hardcore s/m relationship and story that could use some hefty writing clean-up.