Virat has the sense of guilt and has the sense of realization that what he did is wrong. That is what I like about his character. He also knows the wrong he has done is not a mistake but it is a crime. Everytime he has this sense of realization. I am not justifying his actions right, he doesn't thinks before acting and regrets. That what every human should do. People's ego is bigger than their sorry in reality. So they forget to speak a sorry, he speaks sorry. For what he has done, A mere sorry wont work he has to suffer. He told rightly Sai is like a flower. Flower has a truth of its fragrance. Sai is truthful and so the truth always comes out.
Virat said that came with a hope, but he has pain in his heart. Sai had no hope but still she has pain in her heart. Pain of Sai is real, but hope of Virat is real. But for hope to shine, pain must end. Till pain of Sai wont end, hope of Virat has no place. She said "First you give me the pain and then you come with the hope that I will heal". Till the pain ends, hope wont start at all.
Usha saying Sai should go with Virat, was right but after some time not today. The some time is her period of shining in her career. Virat saying come back for Aai, Sai was in anger and in pain so she said to Virat "Sharam nahi aati aapko?" But Sai what you do if Pulkit would say Devi ke liye mere ghar pe sirf kuchh dino tak aa jao, then how would she react? Her reactions will be different.
Sai was definitely much practical and Virat still doesn't knows how the family behaves with Sai even at his back. Even though she forgives Virat, she should not go back to the CN
My opinion
Virat should leave why he was all after Sai, if Sai saying that the house is not her happiness. If he says he loves Sai, then he should leave her for now. Time heals everything.
Last line we heard "Stubbornness spoils the relationship" Its from both the sides. When one bends other is straight. In order to make a relationship successful, both has to bend. But Sairat only one bends everytime and the other is stubborn. That day Virat was stubborn and today Sai stubborn ( for genuine reasons).