I don't think she's tolerating abuse. She jumped out of balcony with Savi when he caged her. She rejected him. She took bis challenge of not finding another man and showed him she's not interested. Just before cake cutting she spoke up for Satya, Amba fiercely.
Shes made clear that she wont tolerate his crap.
But she can't cut him off. She has to be the civil one when he's being a jerk to ensure someone is watching over Vinu and handling him . Infact i think her look was even one of telling V that - dekh lo, no thanks to you my son is calling me Aai of his own accord.
The makers tricks of doing slow mo or BGM to force romance is not gonna make any sane audience accept it.
Satya expression was of mild discomfort and essentially an acknowledgement of the fact that these 2 estranged people ideally should have been a happy family with their kids but they aren't. But he also knows its not his fault that they aren't together. Or Sais. Its all on V.
