The Lunatic Cafe by Laurell K. Hamilton
'You don't volunteer for slugfests with vampires. It shortens your life expectancy.'
And you don't fall in love with a werewolf. It interferes with your work. Especially when you're a preternatural expert, like me. My name is Anita Blake. My business brings me up close and personal with all shapes and sizes of monsters. And not all of them want to kill me.
Take, for instance, the local pack of lycanthrops - they're werewolves to you. A number of them are missing, and they've come to me for help. Maybe because I'm dating the leader of the pack. I've survived a lot - from jealous vampires to killer zombies - but this love thing may kill me yet.