By the Rosemary Tree by Abigail Bridges

Different lives. Different cultures. An insurmountable chasm. But an unconquerable love.

It was impossible, the love that Philip Ashton, Marquess of Kennet, had for Emalyn Benjumeda. Although they had been friends since childhood, Emalyn is the descendant of Andalusian and Moorish wine merchants—a foreigner. A forbidden match. When Philip’s father, the Duke of Kennet, suggests Philip keep Emalyn as his mistress, Philip rebels. He does not want the love of his life as a mistress—he wants her as his wife and the mother of his children.
With their parents against them, and more appropriate matches being lined up for both, Philip and Emalyn struggle to stay together. Desperate enough to ruin them both, Philip turns to an unexpected ally.
What will it take to keep Emalyn in his country—and his life?