I feel like this is a great point. I didn't get a chance to think about this until you brought it up, so thank you. I think that when Ashwini sees Virat, he is the reflection of her responsibilities while Sai is the reflection of her helplessness.
By this, I mean that she sees Virat as someone who struggles with just how many responsibilities are on his shoulders. She herself sacrificed many things, including her own happiness for the sake of responsibility. However, she doesn't regret her responsibilities, she regrets the helplessness she felt when dealing with them. That helplessness she sees in Sai, not in Virat. Maybe if she looked a little closer than she could see that Virat is more like her than Sai is. Sai is like the perfect combination of Bhavani and Ashwini, righteous but outspoken. Virat on the other hand, is probably like Ashwini was when she was his age. Suppressed and quite alone. Maybe if he was called stupid, unintelligent, and small constantly, the way Ashwini has been, he would have turned out as quiet as she is. However, his family brought him up calling him smart, athletic, the ideal son, and the ideal human. He has self-confidence and a feeling of belonging in the family, something that Ashwini lacks. Still, Virat continuously sacrifices and keeps his pain to himself. Whenever Sai is hurt, she goes to Ashwini. Where do Ashwini and Virat go? They both internalize and suppress their thoughts. However, Ashwini lets go in a healthy manner by supporting Sai and being her backbone, while Virat expresses his emotions inappropriately, at the wrong time, or in the wrong manner. He doesn't support Sai the way that Ashwini does because he feels like he owes the rest of his family some allegiance. They had treated him so well all these years after all. Ashwini, on the other hand, doesn't believe she owes them anything (and rightfully so) so she completely supports who she knows is right. In other words, she puts all of her eggs in Sai's basket. When she sees that her son saves some allegiance for the rest of the family, she sometimes sees him as part of them and doesn't feel like she owes him anything. This is where things get complicated between Virat and Ashwini.
This is all my interpretation and is more than likely incorrect, but I just wanted to put my thoughts out there :)
oml there is so much more to say but by then I'd be writing pages lol