Julia Quinn 
Because of Miss Bridgerton [EPUB ebook] 
A Bridgerton Prequel

Sometimes you find love in the most unexpected of places…This is not one of those times.Everyone expects Billie Bridgerton to marry one of the Rokesby brothers. The two families have been neighbors for centuries, and as a child the tomboyish Billie ran wild with Edward and Andrew. Either one would make a perfect husband… someday.Sometimes you fall in love with exactly the person you think you should…Or not.There is only one Rokesby Billie absolutely cannot tolerate, and that is George. He may be the eldest and heir to the earldom, but hes arrogant, annoying, and shes absolutely certain he detests her. Which is perfectly convenient, as she cant stand the sight of him, either.But sometimes fate has a wicked sense of humor…Because when Billie and George are quite literally thrown together, a whole new sort of sparks begins to fly. And when these lifelong adversaries finally kiss, they just might discover that the one person they cant abide is the one person they cant live without…