To Love and Serve - The Calling is Reborn Vampire Novels, #13

He lived alone for centuries until she came into his life .Southern vampire Ryder Latimer had never expected to love again or to live again until FBI Agent Diana Reyes came into his life and made him believe it was possible to believe in the future.  When a mission goes horribly bad, Ryder risks his life to save his lover.  When he takes a bullet for her, he contaminates her with his blood, saving her life, but condemning her to a slow death as his vampire cells take over her body.
Since her father's death years earlier, she had dedicated her life to protecting others ... Diana Reyes's father had died in her arms and since that date, she's served others in order to obtain justice and keep the world safe.  When sexy Ryder Latimer saunters into her life, he challenges what she believed was meant to be her life.  There's just one problem:   Now when she really believes in the possibility of happily-ever-after, her life is slipping away from her and Diana must decide whether to become a vampire in order to stay with the man she loves.