Enchanted No More. Robin D. Owens

As one of the last surviving Mistweavers, half-blood Jenni knows what it's like to be caught between two worlds: the faery and the human. But the time has come to choose.The Lightfolk require her unique talent for balancing the elements to fend off a dangerous enemy – and rescue her missing brother. Only for Rothly will Jenni deal with those who destroyed her life. Only for him will she agree to work with her ex-lover, Tage, and revisit the darkest corners of her soul. For a reckoning is at hand, and she alone has the power to hold back the forces of dark.