Instead of showing Sai can't understand the feelings of Virat, it can be better shown that she feels Virat is not a trustworthy man.
Does a man who loved a woman so deeply that he gave promise on her wedding day and informed his commitment for pakhi to his wife before marriage has moved on so quickly and told both his ex and current wife that he won't live on past, a trustworthy fellow?
He thought Pakhi to be the ideal bahu for his family and understood Sai to be fierce and selfless. Now after a year or 5 years if he finds another woman of his department who is both fierce, caring, selfless and ideal bahu material, will he again move on and say Sai that I won't live in past, you can move on and live an independent life and be a successful doctor?
Will anyone trust such a character? He is certainly not a two-timer but a traveler. His love comes with validity period.
If Sai feels like this good way to go for storyline.
3