The Wager of a Lady by Kathleen Ayers

The notorious bastard of a duke.
Leo Murphy believes in playing the odds, as long as the house wins. As the owner of Elysium, London’s most exclusive gambling hell, Leo’s existence depends on predicting his opponent’s next move. Rarely is he surprised. Until he meets the Lord Masterson’s young bride losing at cards.Georgina is beautiful, intelligent, possessed of a razor-sharp wit and a rebellious nature.
She is completely unexpected.
Leo is so struck by Georgina he doesn’t know whether to bed her or befriend her. He decides to do both.

A rebellious young American.
Wed to the scandalous and elderly Lord Masterson, Georgina detests London. Mocked for her accent and her family’s pedigree, she wants nothing more than to return to New York. When the wickedly attractive Leo Murphy offers to teach her how to play cards, she assumes he merely wishes to admire her bosom. She’s half in love with him before the evening ends.

A wager that ruins them both.
One unforgettable night with Leo leaves Georgina compromised in both heart and body. Now she’s keeping secrets from everyone, especially Leo.
Will he forgive her? Or let Georgina go forever?