What is the name of the woman Piri's father is having an affair with?

Piri’s family moves to Long Island after his father saves enough money that allows him to pay for a down payment on a small house there. Piri does not like Long Island, because its social scene is totally different from the Harlem social scene that he is used to. It is while his family is living in Long Island that his mother talks to him about his father’s infidelity. She tells him that his father is seeing another woman called Ruthie. It seems that Piri too has known about his father’s infidelity, for he states that “I knew it, too, but I’d lie my ass off to make it a lie so that Moms wouldn’t have to make it any harder for herself.”
Piri struggles with race issues. He takes after his father and is darker skinned than all his siblings. Even though he is Puerto Rican, he is sometimes as black, much to his chagrin. As a child, he even suspects that his father maltreats him because of his dark skin. In trying to discover himself and his place in his society, Piri is entangled with the difficulties of street life, becomes a junkie and a criminal, and finally lands in jail.