What led up to the fight between Charlie and Pete on Mary's tenth birthday?

On Mary's tenth birthday, both parents took her out and spoiled her. Charlie took the girls shopping and out for an expensive lunch even though money was tight for the family. When Pete heard about this, he and Charlie began to fight and Charlie threw the lasagna she made for dinner at Pete as he stormed out of the house. When Mary came downstairs after the fight, she found her mother serving birthday cake for dinner, and her father sitting alone in the dark garage.