Her Vengeful Scot - The Highland Warrior Chronicles, #2

My enemies will pay for what they've done Cameron MacNeil pledges vengeance on the Pict noble who killed his sister. But he didn't expect to fall for the beautiful pagan princess - his enemy's widow, Elise. A secret that could tear them apart forever... When danger threatens her life, Cam risks everything to keep her safe from his king's machinations. He should be happy now his enemy is dead, but guilt cripples him at the secrets he must keep, for if Elise ever discovers the truth, he'll lose her forever. An unwilling betrayal... But Elise has a secret of her own, one she is blood bound never to reveal.
Even if keeping it means she'll lose the only man she's ever loved. "Phillips' evocative writing style will draw you back in time and take you on the ride of a lifetime."