Precious by Athena Steller

Drake had no idea when he took a human’s blood in order to perform a duty for his family that the human was his mate. One taste and Drake’s world is rocked. Now not only does he need to convince the human that Drake is his forever, but Drake also has to teach Lawson how to fit in with his paranormal family.
It had started so innocently. A visit to a club so Lawson can play as a pup. A man turns into a bear, he gets swept away by a handsome stranger, and learns that vampires are real, and he’s supposed to be a mate to one. Life has never been fair to him, but this time Lawson thinks he’s way over his head.
Will Lawson find the family he’s been searching for or will the paranormal world be too much for him to handle?

Precious is set in the same timeline as Trinity, the second book in the Unlocked Mates series. It is highly recommended to read these books in order, to follow along with the characters first meeting their mates.