A Duke a Dozen by Shana Galen

They call him the Doomed Duke.
Phineas Duncombe, ninth Duke of Mayne, should not be the duke. After all, he had four—count them—four older brothers! Phin never wanted the dukedom, and the suspicious circumstances of the eighth duke’s death lead Phin to question the Countess of Longstowe. The beautiful widow isn’t at all what Phin expected. He’s intrigued by her and determined to seduce her. The countess is not interested in Phin romantically, but when she comes to him with another request, he can’t deny it. A few days in the country with Lady Longstowe reveal two truths to the new duke. One, he cares for the countess much more than any other woman he’s ever known. Two, Phin either has very bad luck or someone is trying to kill him.

They call her the Wanton Widow.
Annabel was barely eighteen when she was married to the elderly Earl of Longstowe. A harsh, sadistic man, the earl’s death was not something Annabel mourned. Now in her mid-forties, Annabel enjoys her widowhood and has no desire to ever be under a man’s thumb again. Not even a handsome duke like Mayne, who is far too young for her anyway. Annabel’s one desire is to find the daughter who was taken away from her. For that she needs a man with power and status. She needs the Duke of Mayne. When the two are thrust together, Annabel struggles to fight her attraction to the charming Phin. She’s losing the battle. But can she ever trust another man, especially with the one part of herself she’s never given away—her heart?