Bitten By Mr. Darcy by Valerie Lennox

His name has not always been Mr. Fitzwilliam Darcy in his centuries-long existence as a vampire, but it is now. Enduring a stay in the country with fellow vampires the Bingleys, he scents a woman who drives him mad with longing.

Elizabeth Bennet, his sirensong.
He cannot stop himself from tasting her, fitting his sharp fangs to her neck and drinking her honeyed, intoxicating blood.
But he is a noble sort, and he does not wish to destroy her with his attentions. He walks a tightrope between his maddened desire for her and his attempts to keep himself in check.
She is so young and fresh, her whole life ahead of her. It would be wrong to pull her down into the dark with him. He must resist.

Dear reader, I wanted to write about a vampire Mr. Darcy who was more like Lestat, but Mr. Darcy is very definitely Louis, maybe even just Edward. He has so many scruples! This version is steamy, so be aware. Angsty, too, of course. I promise, though, everything works out in the end.