So Twisted by Melissa Marino is the first book in her Bad Behavior series. A debut novel with the story told in dual POV, the main charcaters are Aaron and Callie. 
 Aaron is a single, divorced father of a four year old daughter Delilah. His ex-wife has been out of the picture since Delilah was a baby and he finds himself in need of a nanny. Aaron is a serious soul, his main concern and love in his life is his daughter. She is his whole world. 
 Callie is getting her degree to become a teacher. Working nights as a bartender and studying hard during the day, she is burning the candle at both ends. When her best friend finagles the opportunity to interview for a nanny position that will ease her workload and allow her to at least get a normal nights sleep, she can't say no. 
 These two together, it was pretty much insta-lust with a rapid fire relationship shortly after. A bit of drama and angst towards the end but, thankfully, they do manage to find their way back to each other. This story is a standalone within the series and while the series is better enjoyed in order it isn't necessary. Callie and Aaron's story is complete but they cameo in the next two books, So Screwed and So Wicked.