"Lover Extraordinaire" is a romance novel written by J. Lynn (Jennifer L. Armentrout), and it is the third book in the "Captive in the Dark" series. However, I believe you are referring to "Lover Extraordinaire" as a standalone novel featuring Cora Reilly as the main character.
: As their passion intensifies, Nora finds herself falling for Adrian, a man who explicitly "doesn't do relationships". She struggles with her desire for love and commitment while fearing that admitting her feelings will end their arrangement. The Resolution