To Defend a Damaged Duke by Fearne Hill

Benedict Fitzsimmons, the reclusive fourteenth Duke of Ashington, nurses a secret desire for his own sex he’d much prefer nobody ever found out about. Indeed, having only ever given in to his urges as a youth—and with disastrous consequences—he never imagined they would. Preferring the company of his racehorses to people, Benedict spends most of his time working on estate matters, longing for a lost love he can never have.
When an anonymous letter threatening to expose Benedict lands in his lap, he’s shocked to the core. He doesn’t have any enemies; why would anyone want to destroy him? Terrified, and with his family’s impeccable reputation at stake, Benedict joins forces with loyal friend, the Earl of Rossingley, to track down the culprit.
Risen from poverty and with a sordid past he’d rather forget, Tommy Squire has a mind dedicated to growing his business ventures and a heart shaped from stone. When the man who once broke it in a life-changing betrayal requests Tommy’s help to avoid a scandal, he finds himself embroiled in a daring scheme to bring down a blackmailer. As their plot unfolds, Tommy realises it’s more than his former lover he’s endeavouring to protect, it’s his battered heart.

This second book in the Rossingley Regency romance series turns to friends of the fourteenth earl of Rossingley, Lando Duchamps-Avery, who once again has a hand in the shenanigans set in London’s wealthy Ton society. This book can be read as a standalone.