personally, i think garv and kali are to blame equally! it was wrong of garv to cheat on kumud and kali is just so thick headed and can't get it through her head that after everything is out in the open that garv will never love her. he loves kumud and after such a big betrayal he won't ever be able to forgive kali.
kkusum is also to blame a little for what has happened. kkusum and everyone else has forgiven kali for everything she's done so to her it's alright to go around destroying and hurting whoever she wants. if abhay had taught her some manners and respect and morals then she wouldn't be like this. but what else can you expect from a spoiled brat like kali!