Ruth's parents' relationship is collapsing because her father is having an affair.
Ruth is living with Dennis when her father tells her that her mother is sick and they need help with the store. Although she does not want to, Ruth returns to Suffolk for what she believes is just a few weeks to help her mother. Unfortunately, when she arrives home, she discovers that things are worse than she had thought.
Ruth's mother is
"a good Jewish wife who (keeps) true to her religious faith, and she let(s) a lot roll off her back...because her husband (isn't) worth a dime and she (has) no choice. The way Tateh treat(s) her, they'd call her an 'abused woman' today. Back then...a man could do anything he wanted to his wife in the South. He can yell at her, make fun of her, curse her, slap her. He can even go out with another woman right in front of her face".
Ruth's father does indeed have another woman,
"a big fat white lady...as big as (the) living room. She live(s) not far from us up the road. Her husband (is) serving time in the county jail...for being drunk or some petty crime like that...she (has) four or five kids. Tateh would talk to her in the store and try to act like it (is) casual; then on Friday nights (he) would go out...pack a bag of groceries and throw them in his car while Mameh watched him".
He would not return until Monday.
Ruth's father's affair becomes "full-blown" very quickly". He soon demands a divorce, but Ruth's mother refuses, as she has nobody else to look after her. Eventually, Ruth's father goes to Reno, Nevada and gets a "quickie divorce" despite his wife's objections (Chapter 19).