My Roommate is a Vampire by Jenna Levine

Two strangers. One apartment. Will it be love at first . . . bite? Cassie Greenberg needs a new place to live, and fast. When she finds an affordable apartment in a beautiful neighbourhood, she knows there must be a catch. Of course, her new roommate Frederick J. Fitzwilliam is far from normal. He sleeps all day, is out at night on business, and talks like he walked out of a regency romance novel. He is also leaves Cassie heart-melting notes around the apartment, always asks about her day, and doesn't look half bad shirtless on the rare occasions they're both home and awake. There's no denying there's a spark between them - but there's also a secret. . . With true love at stake, will Frederick come clean?