Crosstown Crush by Cara McKenna is the first book in her new Sins in the City series. Oh-Em-Gee, the things you learn about reading romance and erotic romance. Phew. This book was hot off the burner, scorching hot. 
 Samira and Mike have been married together and happy. Mike has a fetish of sorts that is explained simply as a cuckolding fetish, and a little better as he has ultimate control and responsibility in his job so every once in a while, in a "play" setting, he wants to feel like the lesser man, have his wife "cheat" on him, and then take the opportunity to "take" her back. It's very sexual, highly-charged, and works for them. Samira decides to see if Mike wants to take it to the next level. Instead of an imaginary "other man" should they invite a third person into their play time? 
 I literally could not put this book down. It is a not as common fetish that is well-written and the balance of power and emotion between the relationships that evolve is phenomenal. I finished this in a couple of hours and needed a cold shower afterwards. Prepare yourself people - did I mention this was hot?