I see the similar traits in Mrs. Malik as well. So she found out about her Husband's affair. And from the scene it looks like right on her daughter's wedding day. The way she questioned him - how could you do this!!
She was a mature woman with grown up kids.. and still she got so engrossed in her own pain that she forgot about her kids. About her daughter who is ready as bride.. about her son who is apple of her eye and needs his mom. She did not even wait to get Anjali married before start thinking about her own marriage life. The children didnt matter to her. Her, who was asking her unfaithful husband minutes ago how could you do this to me... you did not even think about your children.
She chose to kill herself within minutes, leaving her kids in pain. What a weak and selfish lady!! If anybody is responsible for painful past of Arnav and Anjali, its their own Mother, who chose to abandoned them... It was her why Anjali was left stranded at the alter and not Garima.
I know this aspect will never even be raised as no one is supposed to bad talk about dead... but thats the impression I get about her...