Duke of Rath by Mariah Stone

Beauty tames the beast when a marriage of convenience becomes anything but convenient for a duke with dark secrets.

Haunted by a dark secret, Dorian, the Duke of Rath, is consumed by wrath and guilt. The powerful lord will endure any torture to atone for his sins, even marry a perfect stranger—his victim’s little sister—to save her family from ruin.
He vows not to touch her and to protect the innocent girl from his depraved sensual pleasures. But she must stay for one year and follow his strict rules.
When botanist Miss Patience Rose walks down the aisle in her simple dress, with garden soil permanently embedded under her short nails, she lets a little sunlight into Rath’s blackened heart.
Young, innocent Patience drives her older husband mad with her cheery chatter and her irresistible curves
She’s breaking every one of his rules.
He punishes her…and she likes it.
Love is healing Rath’s soul and transforming his bleak, imposing mansion into a warm home.

There’s just one thing keeping them apart—the ghastly secret that could send him to the gallows. And Patience is putting her brilliant mind to work to uncover it.