Page 29:
A husband shows respect for his wife by being sensitive to her physical and emotional limitations. Whenever possible, he will help his wife with domestic chores. Like Jesus, a husband will be willing to carry out menial tasks humbly, not shunning such work as somehow being beneath his dignity. (John 13:12-15) Instead, he will view these chores as an opportunity to show his love for his hardworking wife. She will greatly appreciate wife such help.
Or in other words: A woman is physically and emotionally more fragile than a man. As her husband you should help her. Yeah, we know, the work that a wife performs at home does not require much skill, so we know it is a bit humilitating for you to help her with the cooking and cleaning. But remember, if you do sacrifice your dignity in this manner, then your wife can work harder and earn more money.
By the way, this must be new light. In the WT 2006/9/15 p. 26 paragraph 4 it was suggested that a married woman should not work outside the home, as this could lead to adultery.