The Wyndham Legacy by Catherine Coulter

Marcus Wyndham never asked to become the Earl of Chase. The Duchess never asked to be illegitimate. And neither of these two asked that their fates become so entwined.

Marcus is passionate, quick to rage, just as quick to laughter. He's tough, opinionated, domineering, known as the devil's own son. The Duchess is serene and aloof -- she has silence down to a fine art. She is always in control, her smiles as rare as bawdy jests in the pulpit. She is self-reliant once she realizes that a very special talent can make her so, a talent no one suspects.

Surrounding this unlikely pair are three servants cast in the Shakespearean mold: Spears, Badger, and Maggie -- all cocky, smart, good plotters and better friends, who don't know the meaning of subservient.