Check out the Casual Rule by AC Netzel: HERE.
Julia Conti is living the dream in New York City. She has a job she loves in publishing and shares an apartment in the Village with her lifelong best friend, Allie. Following a bad break-up, Julia swears off of men and relationships, until she meets Ben Martin, an up and coming author who is smart, sexy and very easy on the eyes. Fueled by their mutual attraction, close working relationship and fear of relationships, Julia and Ben embark on a purely physical affair, following the Casual Rule. As they bring each other further into their lives, their casual status blurs. Can she keep sex and love separate or will feelings take hold and Julia get her heart broken again?