Wicked Lovely by Melissa Marr

Aislinn has always seen faeries—dangerous, beautiful, and utterly invisible to everyone else. She has spent her life avoiding their attention, living by the rules that keep her safe. But when the Summer King, Keenan, sets his sights on her, everything she knows begins to unravel. Drawn into an ancient power struggle between light and dark, Aislinn must choose between the mortal life she craves and the immortal destiny she never wanted. As desire, danger, and deception intertwine, she discovers that love—like the fae world itself—can be both wicked and lovely.