The characters are so fleshed out and even though there is a slight tinged of fairy-tale to the situations, each scene is believable. Like, this could really happen. Who hasn't imagined the perfect boyfriend? Maybe used him to get out of an awkward situation... and then have to dump him in order to date the real deal (not me, that last part has never happened).
Grace Emerson, 30yr old, lies about her new "boyfriend" so that her little sister doesn't feel guilty over dating Grace's ex-fiancé (which he left Grace because he fell in love with the sister. Asshole). Which is fine, until Callahan O'Shea (or O'Hunk) the not so perfect man moves in next door and throws her hormones into a frenzy. Too bad she's already spoken for.
This is what romance should be, no, what all works of fiction should be; entertaining! Emotional! The hardest thing to stop reading!