The Lion and the Leopard (The Knights of England Series, Book 1) : A Medieval Romance

Maria wishes to be a dutiful wife, a task which should prove easy. She's eloped with Phillip Rendell, the knight about whom minstrels sing, and who saved the life of Edward II's half-brother, Richard of Sussex, at the Battle of Bannockburn. But Phillip will not happily settle as husband and lord of Fordwich Castle, and Maria fears he bears the mark of Cain, always seeking something more, something just beyond his reach. And while Maria still desperately loves her restless husband, she is also drawn to the powerful man he saved, and he to her.