His statement , "Haq apno ko dhiya jhatha hai..." and her reaction...,"aur mein toh tumari apni nahi thi" with an expression that showed so much of pain..
Sonakshi as person prefers to do things by herself...I guess its a habit that was developed at a young age...now you get to see that in Soha...But for a person like Dev he doesnt understand this . For him, other than his work related activities everything was done by his mom..So whenever Sonakshi tries to do by herself , he thinks it be pride ego etc...But if you have noticed.. she takes help only from ppl she thinks has accepted her as their own...in the initial days of marriage when she couldnt withdraw money from the ATM , she had asked Dev to give her money...and she behaved just like any wife would do...
Now when he said that Haq apno ko dhiya jhatha hai...she felt how could she take help from him when he doesnt consider her to be anywhere close to him...not even as a friend...
He realised that she was hurt by his statement ...hence the sad and lost look when she didnt take his hand twice...