Who is Aunt Betty Weller from The Cape Ann and what is their importance?

Aunt Betty Weller is Lark's maternal aunt. She is hopelessly in love with Stanley Weller. While pregnant, Aunt Betty was bedridden and extremely ill. Sadly, her child was a stillborn baby girl. After losing her child, Aunt Betty embarked on an affair with a married man. In the novel's conclusion, she is living with Arlene and Lark.