A Duke in the Night by Kelly Bowen

Duke. Scoundrel. Titan of business. August Faulkner is a man of many talents, not the least of which is enticing women into his bedchamber. He’s known—and reviled—for buying and selling companies, accumulating scads of money, and breaking hearts. It’s a reputation he wears like a badge of honor, and one he intends to keep.

Clara Hayward, the headmistress of the Haverhall School for Young Ladies, on the other hand, is above reproach. Yet when she’s reunited with August, all she can think of is the way she felt in his arms as they danced a scandalous waltz ten long years ago. Even though her head knows that he is only back in her life to take over her family’s business, her heart can’t help but open to the very duke who could destroy it for good.