A Raisin in the Sun is a play about an African American family's struggle to rise into the middle class. Everyone in the family has their own personal ambition, and the conflict in the play arises from disagreement over how best to use a sudden windfall—a $10000 insurance payment. Walter and Ruth are a case in point. Walter, ambitious and headstrong, wants to use the money to invest in a business with his friends; his wife, Ruth, on the other hand, has sided with Walter's mother, the head of the family, and wants to use the money to make a down payment on a house.
I think Walter's relationship with Ruth is like his relationship with his entire family—on the one hand, he views Ruth and her pregnancy as a weight that is dragging him down, but on the other, by the end of the play, he has come to understand that family is more important than personal ambition. The turning point comes at the end of the play. The mother has used the money to make a down payment on a house in a white neighborhood, and the community association has offered to pay them not to move in. Walter has decided that they should take the money, but when it comes time to sign the papers, he changes his mind. He realizes that the good of his family is more important than any personal ambition he might have.