My Hero by Glynnis Campbell

Wealthy and powerful, the de Wares are one of the most respected noble families in England. The heirs to the de Ware legacy—Duncan, Holden, and Garth—are true warriors…and reckless lovers…

Unlike his brothers, Garth de Ware had always preferred peace to war. As the youngest son, there were few opportunities for him to earn his fortune, so he chose a career in the Church. And when a beautiful but cruel woman spurns his youthful passion, he retreats to a monastery, convinced that this is the only life possible for him.
Lady Cynthia le Wyte has always cherished her memories of the boy who was her ideal hero. So she is overjoyed when he arrives at her castle—and stunned when he is revealed to be the new chaplain. The tender, sensitive, and loving boy of her memories is replaced by a stern, brooding man of the cloth who rejects the world and all of its wonders—including Cynthia. She is determined to befriend Garth, to show him the beauty of the world around him, and to re-awaken him to life. But instead of as a friend, Garth sees her as the ultimate temptation—and now Garth must choose between a lifetime of piety and the love of a lifetime.