So Sai has always been intuitive about Virat and Pakhi. She was convinced of a relationship probably when the pyaar- dosti slip happened and she hasn't gotten enough reasons yet to believe otherwise. But why is Virat not clarifying himself especially after Pakhi making her intentions clear to him.
During Ladakh track when the issue was brought I think Virat was uncomfortable in discussing the past and was caught off guard. H wouldn't have imagined Sai confronting with him straight questions about Pakhi then. Sai has repeatedly voiced her insecurity about Pakhi and honestly, it's a weird equation when they are staying under the same roof.
I don't want Virat to confess his love but what's stopping him from clarifying his past to Sai now that he is fully aware of his feelings. He can't begin unless he makes a clean slate. See even during ousting drama, neighbourhood confrontation Sai made it clear Pakhi is behind her husband. She is clearly bothered and insecure over Pakhi and has voiced this n no of times. She wouldn't even think of giving their relationship a chance because of self-respect and the promise she once made to Virat that she would never come in between his promise.
The onus is on Virat to clarify about Pakhi than give shocked reactions every time Sai talks about Pakhi. Sai needs verbal assurances. He can't rely on his romantic gestures to make her aware that Pakhi is his past. Just like how articulate he was about someone is in his life before marriage he should speak up now too. I don't want too many misunderstandings between them. This is a perfect opportunity for the makers to start their love story by clearing Pakhi.