My roommate is a vampire by Jenna Levine

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 also leaves Cassie heart-melting notes around the apartment, cares about her art, and asks about her day. There’s no denying there’s a spark between them – but there’s also a secret. Cassie’s roommate is a vampire. But with true love at stake, will Frederick come clean?