Wolf Duke by Nicola Davidson

After the suspicious death of his mate, Alaric Dafydd Beaumont, King of the Western Lands resigned himself to a future as bleak and isolated as his Welsh Marches castle. But his world keeps unraveling: the soulless outcast controlling the Eastern throne regularly sends raiding mercenaries, then the wretched new human king Henry VII insults him with a dukedom. However, when a missing Eastern princess claims sanctuary, Alaric learns his whole life was a shocking lie. For this bold, lusty she-wolf is his true fated mate and happiness beckons…if he can keep her safe.
With an usurper on her dead father’s throne and a bounty on her head, Evaine de Wynter has been running for ten endless years. King Alaric offers far more than refuge; the handsome and brooding alpha crowns her queen and teaches her unimaginable pleasures. Yet once they begin a royal tour of Wales, new threats and old betrayals are revealed. For a powerful enemy is coming, one that could destroy their love and end their reign forever…