Lord of Sin by Susan Krinard
One act of passion An eternity to pay...
Nuala is descended from ancient witches, eternally bound to help others find love. But after her husband's death, she has no such dreams for herself. Until she meets Sinjin, the Earl of Donnington... Handsome and scandalously tempting, Sinjin has never met a woman he couldn't seduce. Yet from the moment he sees the stunning young widow, he knows he wants more than just one night of sin! But first he must free her from her immortal bondage, which means robbing her of her magic for all time...