Before blaming the BAHU let us blame the legal system for creating such a BAHU. These laws tend to westernize india. In western countries parents dont care for children and children dont care for parents. We are heading towards that. I have seen the kind of lonely lives the westerners lead. I prefer our tradition and culture which is having more harmony. Modern BAHU does not like the husband's mother and sister to stay in the same household.
Now let me come to your issue of why not blame the son... Son wants his mom and sister to live happily in the house. But everyday his wife throws tantrums on his mother and sister. Unable to bear this anymore his mother and sister feel they get peace of mind outside that house and move out. This is what is happening in most of our houses. SHAME ON WOMENS ORGANIZATIONS FOR CREATING LAWS WHICH FAVOR A DAUGHTER IN LAW AND HARASS MORE WOMEN IN THE HOUSE. I WANT ALL THE MOTHERS AND SISTERS OF HUSBANDS TO BOYCOT THE WOMENS DAY.
