The Lady of the Rivers by Phillippa Gregory

Jacquetta, a young French noblewoman is married off to an English lord, the Duke of Bedford, who is only interested in her inherited ability to see into the future.  In fact, he even thinks he has to maintain her status as a virgin in order to preserve her powers.  His interest is in foretelling the location and outcomes of future battles with the French.  This tells the embellished story of a historical character, during the Wars of the Roses in 1400s England and France.  Jacquetta soon tires of her solitary husband and his narrow interest in her as a fortune teller, and of course falls in love with one of his squires.  Conveniently, the Duke falls ill and dies, leaving Jacquetta free to marry her lover, an act which results in a heavy fine from the king and loss of her wealth.  The story follows the intrigues of the royal court of King Henry VI.  While Gregory is a well-respected writer of historical fiction, I found a number of the plot twists to be implausible, and she puts modern criticisms of the place of women in the culture into the mouths of the characters. She does paint a very vivid description of the setting and the historical characters.  435 pages