ANSWER:

This is of no concern to her or her family as she is marrying you and not them. 

Respect your parents and do not go around telling people about their flaws.

QUESTION: Should i tell my future wife that my parents often mad to each other (uncondusif family situation), bcs i didnt want her to be upset if she knows after mariage or it is considered as telling family aib which is prohibited?

Fiqh of Marriage, Fiqh of the family |