The Halacha is that a man is obligated to support his wife financially. In exchange, Chazal decreed that whatever money the woman earns belongs to her husband. (However a woman has the option to waive her right to be supported by her husband, in which case she retains whatever she earns.) The question is if the husband does not actually support her, does he nonetheless acquire his wife’s earnings?
The Chazon Ish (EH 70:6) rules that even if the husband supported his wife only at the very beginning of the marriage, he still retains ownership of all her subsequent income. Since he was providing for her when she earned her first paycheck, he acquired that paycheck. When he uses that money to support her, he has provided her needs with his own money. That entitles him to acquire the next paycheck. This cycle repeats itself, causing the husband to perpetually acquire his wife’s income.