Who is Lydia Vance from Women and what is their importance?

Lydia Vance is a thirty-years-old, has long brown hair, a prominent nose, good breasts, and an attractive body. She writes bad poetry, though she is a somewhat successful sculptor. Lydia has two children, Tonto, an eight-year-old boy, and Lisa, a five-year-old girl. She meets Henry Chinaski at the beginning of his literary career, and they maintain a tumultuous but long-term relationship based on sex. Henry finds her youth attractive and in the beginning, he finds her irresistible. Lydia is fond of large crowds, and she loves boisterous parties and dancing..... all things that Henry finds repulsive.