MY POINT OF VIEW AFTER WATCHING.
Sai is only and only trying to help Shivani.
she does not love Virat, though she has noticed him being kind or with a heart and helpful but for her he's only helping her and one day she needs to leave him.
Virat loves her subconsciously though with his eyes he sees his vahini face but he has started feeling for her he said it clearly twice he does not like her talking saying baby baby muah muah....Sai did not understand from his perception because she does not love him....she did not start to really accept him like her husband. saying my husband and accepting this person as one makes a difference.(THIS IS FIXED ON SAI MIND SHE WILL LEAVE VIRAT AFTER BECOMING A DOCTOR THIS IS IT THEN HER AGE ALSO)
Then the male ego triggered Virat jealousy.....
536