The Rigid Duke by Darcy Burke

As a refinement tutor, Mrs. Juno Langton helps young ladies develop the skills and confidence to secure an advantageous marriage. Her cheerful disposition never wavers no matter how challenging her assignment. When a house party provides an opportunity to match her difficult charge with a duke, Juno will go to any lengths to satisfy her employer and ensure the young lady’s future. Too bad the duke is an unsmiling, rigid grouch, albeit an irritatingly handsome one.

The Duke of Warrington dislikes social gatherings and despises the Marriage Mart which makes it nigh impossible to find a wife. He plans to secure his future duchess at a house party, but she’s being managed by a thoroughly meddlesome—and provocative—Mrs. Langton, who is determined to find his better nature. He’ll do anything to avoid her sunny charm and room-brightening smiles, but she’s breaking through his shell and the only way he can think to keep her quiet is to kiss her. He must marry the young lady, not desire the companion.
But now he’s rethinking his wife choices.