The Good, The Bad And The Undead by Kim Harrison
The second book in the New York Times bestselling urban fantasy-thriller series starring sexy bounty hunter and witch, Rachel Morgan. During the last few months, former bounty-hunter Rachel Morgan has been rather busy. Having escaped relatively unscathed from her corrupt former employers, she's not only acquired a vampiric room-mate called Ivy, faced werewolf assassins and battled shape-shifting demons, but has also found the time to pick up a boyfriend (even if he is only human) and open her very own runner agency. But cohabiting with a vampire, however reformed, has its dangers. Ivy's evil vampire ex-boyfriend has decided that he wants her back, and views Rachel as a tasty side-dish. To make matters worse, Rachel's demon mark is the ultimate vamp-aphrodisiac; one that works both ways. The stakes are high, and if Rachel is to save herself and her room mate she must challenge the master vampire and confront the dark secrets she's kept hidden even from herself.