Is it permissible for the wife to ask her husband for divorce due to his refusal to have children, given his difficult financial circumstances, especially since she has one child and is 33 years old?

Childbearing is a shared right between spouses; neither has the right to prevent the other from it without a valid excuse. The wife should try to understand her husband and be patient with him, and not threaten him with divorce if he insists on not having children. Perhaps Allah will bless them with righteous offspring.