If you liked reading about Bella and Edward in the Twilight series, take a look at Impossible by Nancy Werlin. There are no vampires or werewolves, but there is one threatening fantasy character who lurks throughout. He seems so sympathetic and definitely compelling to most everyone he meets.
Lucy Scarborough is 17 and ready to go to her first school prom when unusual things begin to happen. Okay, she's had a few odd things already in her life -- she is the foster child of the nurse midwife who took care of Bella's single teenage mother when she found herself pregnant and alone, and that mother subsequently lost her mind. Every once in a while Bella sees her mother around town, but Bella keeps her distance from the bag lady with the shopping cart, and her friends don't know about the relationship. And her foster father teaches her a version of the folk song Scarborough Fair that he says her mother wanted her to learn, a strangely unsettling version.
But it isn't until after the horrific events of prom night that she realizes there is a curse on the women in her family, and just how terrible that curse is. Can she complete the 3 impossible tasks set forth in the song, or must she forfeit her child to the compelling, sinister, and not quite human man who appears, and succumb to madness as all her ancestors have?
Each of her ancestors was alone in trying to deal with the curse and solve its riddle. Lucy has the loving support of her foster parents, along with Zach, who becomes much more than her staunch ally.
School Library Journal called this book a "romantic fairy tale with modern trappings." I say it's a book that I absolutely had to finish. And all of us will be really lucky if we have someone like Zach in our lives.