Why does Agnes make the journey to visit her husband in London in the novel, Hamnet?

Agnes visits London to confront her husband after he betrays her in several ways: first, by leaving her too soon after Hamnet's death; second, by having illicit affairs with other women in London; and finally, by using their son's name in a play. Agnes and Bartholomew see the piked heads on their journey to the father's apartment in the city, cementing Agnes's belief that the city itself is a culprit in her husband's many betrayals.