Mr Rahman asked 4 years ago

My sister has done a rishta with a man on the advice of my older sister.
My sister (32 years old) with the rishta situation is that she was in a previous bad marriage and has 3 children. Her children are not obedient and she is worried due to her temperament and the children the marriage with this man might break down. The man who she has a rishta with is 36 years old and has never been married with children and has no experience dealing with children. 
Can she break the rishta with this man if she feels that they are both not compatible and there may be problems in the marriage if she continues with the nikah as she doesn’t want to go through another divorce.
please respond, jazakallah.