Knights Vampire — Kryssie Fortune

Betrayed by the Knight Defenders and murdered by his cousin, crusader knight Blaxton de Ferrers rose as a vampire. For nine centuries, he's preyed on the people he once swore to protect. Gradually, as his emotions leach out of him, he forgets how to feel. Then he meets Harriet.

Harriet Mortlake's a strong sassy woman who battles her weight and her temper. Her job is to seek out the ancient secrets of the castle that was Blaxton's childhood home. Instead, she finds the love of her life.

When danger threatens Harriet, Blaxton steps in. Harriet and Blaxton are a match made in heaven. Except... he's a vampire and to fully claim her, he'll have to kill her.