Rukhsar is a mentally sick woman. Her morals are ambiguous and her reality isn't the same as ours. This why I too feel that Zeenat is the responsible one. She should've made her sister seek psychiatric help! Before her truth came out, she's the only one who knew this side of Rukhsar.
As far as Zabeer are concerned, I am sure they will come out stronger on the other side. But I am waiting for as well as dreading Zara's initial reaction to the news!