The women shouldn't feel envious that they have to carry the burden initially, for his job certainly is not easy either. When he takes sannyasa, he has to forcibly give up attachment to his good wife, his loving children, delicious meals, the comforts of home, and strictly control all his senses, absorbing his mind day and night in g and preaching about Krsna. That's not easy. The materially covered senses strongly react against that life-style. And there is no possibility of cheating oneself either. Controlling the mind is the most difficult part. During this time the wife is more or less relaxing and being served by her children and grandchildren. She has done her share of the work and now can simply pray that her husband remains sincere. Of course, she must remain pure and simple herself, but compared to her husband's austerities, she is taking a vacation. So granted, it's a tremendous surrender to be a chaste wife. Her job is very difficult during the time of cooperation together, but the husband has the hard job at the end. If he is fully satisfied with his good wife's faithful service, then his gratitude to her becomes a tremendous impetus to repay her by becoming fully Krsna conscious. If the wife is not devoted exclusively to him however, then he may well be attracted to another woman and thus his life is also ruined. So chastity for a woman is the first religious principle.