The Duke’s Inconvenient Bride by Jayne Rivers

A jilted duke. A shy wallflower. A marriage of convenience that neither of them wants.

When Lady Emma Carlisle’s twin sister jilts the wealthy and influential Duke of Ashford, their distraught parents pressure shy Lady Emma to marry the duke in her sister’s place, dashing her hopes of a love match.
Lady Emma is determined to make the best of the situation, but her new husband is cold, aloof, and wants nothing to do with her. In his quieter moments, she catches glimpses of a thoughtful and intelligent man she’d like to know better, if only he weren’t determined to keep her at a distance.
Lady Emma is willing to offer the duke her heart, but she knows there’s every chance he’ll break it. After all, why would the handsomest man in the ton fall for his second best bride?