Who is Martha Fones from The Winthrop Woman and what is their importance?

Martha Fones is Bess' younger sister. She is described as a weak woman, both emotionally and physically. Martha falls in love with Jack Winthrop, her first cousin, and out of fondness, he marries her. Unfortunately, Martha is afraid of marital relations and of giving birth, and their years of marriage are fraught with depression and angst. While en route to America, Martha tries to take her own life by jumping from the ship, but is rescued and afterward finally loses her virginity, due to Jack's insistence. She later dies of a disease.