She is a mother-in-law to Gunjan and has some right over her and some expectations too. Now, I'm not the one to suggest that she be sub-servient or obey all her wishes and commands. But, she at least deserves to know where Gunjan is going and all, right?
Gunjan herself had promised her a couple of times that she won't hide anything from her. And then she did hid the truth of those villagers trying to hoodwink Mayank from Seema and now she left for Mumbai without telling Seema.
By the way, Seema's every word about Pihu was bang on and right.
PS: Please constructive comments only. We all can have different opinions.