After first roti fight with Rashmi, wen Aarti was asking Sid why he got so angry and told him to control his anger, he said he needs roti, so he fought...then Aarti said roti is not reason, there is something that's bothering him.... little later he said how can Rashmi tell Sana not to trust him or take his side as she doesn't know him and he will betray her...he actually felt bad that Rashmi was trying to instigate Sana against him and he didn't like that and this was wen they started sitting and talking together and Sana helping him with chopping
His possessiveness started back then only and he feared of losing her