From the description:
"When Roger Bigod arrives at King Henry II's court to settle a bitter inheritance dispute, he becomes enchanted with Ida de Tosney, young mistress to the powerful king. A victim of Henry's seduction and the mother of his son, Ida sees in Roger a chance to begin a new life. But Ida pays an agonizing price when she leaves the king, and as Roger's importance grows and he gains an earldom, their marriage comes under increasing strain. Based on the true story of a royal mistress and the young lord she chose to marry, For the King's Favor is Elizabeth Chadwick at her best."
This bit of historical fiction is well liked, 4.4 stars from 29 reviers, with 1 two star review only. Digital list price is $7.99 for 530 pages of historical fiction