Why does mama decide to go on the pilgrimage?

Chea Mirabal decides to take all her daughters on a pilgrimage to Higuey, where there have been sightings of the Virgencita. On the drive there, Chea speaks a bit too flippantly about her husband, and Patria begins to wonder why Mama wanted to go on the pilgrimage. Mama declares, "They're all scoundrels—Dominicans, Yanquis, every last man ... yes, your father, too." She will not elaborate, but Patria understands that her father must have been unfaithful.