Remember Bani was chloroformed in Jannat apts then mysteriously left in a mall. So could be that photos of her with a male were taken in compromising position.
This photos were sent to JW and family. That is why JW appears to cold and uncaring. He believes Bani betrayed him. He is emotionally dead. So that is why he does not appoint a lawyer, sends her to mental asylum to suffer just as he is suffering. She has driven him mad, he was madly in love with his wife. Death would be an easy option. she will go mad just as he is. Perhaps he is even lead to believe that the children are not walias or product of her liason with the other man in her life. He knows she will live for her children. So, he takes them away from her. She will forever be yearning for her children. Just as he can never have peace, she will never have peace. He will take away the most precious thing from her just as she took away his heart and soul.
The man in the photograph will be Tarun. He will be the third person without whom Pia said her plan wouldn't have worked.
Jai Walia is exacting revenge from Bani based on false info provided by Pia.
Now Pia is all set to come into JW's life and she is carrying his child. He will marry her to make his only child legitimate.
This is Pia's chaal and JW dhooka.
Once again they will show that JW doesn't have that much faith in Bani.