Wicked Lovely by Melissa Mar
There are three rules of survival for Aishlin: Don't stare at invisible fairies, don't speak to invisible fairies and never reveal you possess the power of the seer's sight. The old rules are breaking. Keenan, a powerful and alluring fairy begins to stalk Aishlin. Keenan is actually the Summer King and is determined to make Aishlin his Queen.