What a great force is it capable to push honest and respectable image of the girl (Madhubala) to the offense to forgive the nothingarian her mother's offense! Just because she needs a full marriage, and he is just a handsome man?
A man asked the Prophet Muhammad (peace be upon him): "Oh Messenger, who of people is the most worth my good treatment?" He said, "Your mother." The man asked, "And then who?" He said, "Your mother." The man asked, "And then who?" He said, "Your mother." The man asked again: "And then who?" Only then the Prophet (peace be upon him) said to him: "Your father."
Thus, the taboo is not only in abuse of your own parents as such, but also any actions that may lead to the fact that anybody else abuses them.