Makers don't allow Sai s character to go all out . They restrict her a lot, because they want to give all importance and support for P as she s their favourite. No character supports Sai. P always has to be n the frame no matter what. They make Sai whitewash ML and PL. If it was some other PH, Sai s character would have been handled Better.
Even Virat stands like a rock for P, ready to take transfer, hide all her faults. He's okay not to meet Savi. He took Vinayak to meet Sai only because he wanted to talk to her about the case. He's ok if P doesn't send Vinu to school.
But when he was married to Sai, he shared everything about Sai and his life with P, that's why she was able to break them as she knew their weaknesses thru V.