Let's keep aside Pakhi's pre leap wala bad karma. Post leap they showed Virat and Pakhi were married to become the adopted parents of Vinu. Initially they showed Virat was not giving her any bhaav and she was expecting him to accept her as his wife. Later due to circumstances he did accept her as his wife in front of his family. So her first expectation from Virat got fulfilled.
Then her second expectation was to have a child from Virat. Virat took her to HM, he could have done it with her but from this point onwards the circumstances stopped favoring her. She slept off before they could do the deed, then her condition deteriorated and her uterus had to be removed.
Then circumstances made Virat to start looking for his first child but he was still taking care of her, giving her medicines on time etc etc. Then she saw the cafe hug and started thinking that Virat is indulging in an EMA with Sai because she can't give him a child. She had full right to question Virat about the hug but instead of that, she diverted her attention towards Vinu. She kept her rights as a wife on a backburner and focused on Vinu.
Then she came to know about Vinu being Virat's and Sai's first child and she feared she'll lose Vinu too to Sai hence decided to take him away to London but was found right on time by Virat. She threatened Virat of committing suicide if Sai takes Vinu away due to which Virat supported her in the entire Vinu's custody phase. He knew Sai was not wrong in her place but still he supported Pakhi over her because he chose his duty as a husband over Sai's rights as a mother.
After Sai withdrew the case Pakhi got what she wanted, Virat as a husband and Vinu as her son but still her fear of losing these two didn't fade away hence she started poisoning Vinu's mind against Sai and to some extent even Virat with her jadugarni story. The result of that was Vinu chose Pakhi even after knowing that Sai is his biological mother. She created so much fear in the mind of that child that it affected him psychologically and he turned into a weak, timid, hateful boy.
This was the biggest mistake she made and this led to Sai returning to CN. So basically her own karma made her 'sautan' to come back and live in the premises of her home. Now Virat told her he's ok with Sai coming back because she's his second child's mother and as a mother she can stay there. He also promised Pakhi that he will make sure Sai doesn't take away Vinu with her but Pakhi didn't believe him.
I can understand her frustration because Virat's focus has shifted from her to Sai’s and Savi’s safety but Virat gave his explanation too. He told about Ajay Kamble and the threat to Savi’s and her mother's lives. If she was a good and kind person she could have understood his concern but she didn't. When she saw the earring in Virat's pocket she could have questioned him in private in their bedroom but she instead decided to create a tamasha in front of the entire family and tried to prove him to be a characterless cheater. Then she lied to Sai that Vinu threw her lunchbox in the dustbin.
I would have blamed Virat and said as a wife she's right in her own place but after listening to his conversation with BK where he clearly said he will choose his commitment for Pakhi over his love for Sai I can't. If Virat is wrong then that doesn't make Pakhi right either. She failed as a mother by poisoning Vinu's mind and is still failing. As a wife also she failed by not trusting her husband inspite of him standing for her in Vinu's custody case. This is completely my opinion.
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