Dukes to the Left of Me, Princes to the Right — Kieran Kramer

THEIR ENGAGEMENT WAS A FAKE.
Most women would not be pleased to be labeled a spinster. But Lady Poppy Smith-Barnes isn't most women. In fact, Poppy has invented an imaginary fiancé, the Duke of Drummond, to deter unwanted suitors. A very useful fellow, this duke, until the real Drummond turns up and uses Poppy's ploy to trap her in a betrothal.

WILL THEIR PASSION MAKE IT REAL?
A good spy flies below the radar. Which is why being named one of the Prince Regent's “Impossible Bachelors” is so inconvenient for Nicholas Staunton. Every society female will be out to ensnare him. Nicholas needs a fiancée -- and Poppy's ruse is the answer. How could he have known she'd be a brazen, sensual siren with an irresistible taste for adventure? Now nothing less will do than to convince his fiery Poppy to revoke her spinster status…for good.