I found Dev's behaviour odd today. He barely knows Durga and he just walks in the house Unannounced and starts yelling at Durga about her personal life.
And I think the answer that Durga gave him was dig at him for not declaring his love for Nitya before he left for USA. And after he left her, he completely abandoned her for two years.
So I think she was trying to say that now you realize that you loved Nitya then so why did you not communicate that to her then and be there for her when she needed him the most.
Durga knows that the mission she is on she cannot afford to be distracted by feelings that might weaken her in completing her fight for justice.
So she had to be hard and keep Dev safe and away from knowing her real reason.
Dev has to start looking closely at his family and how and what they did to his friends and their family. Till he doubts Shakshi and Rajnath and going to people he knows that they were capable of buying and blackmailing them to change and or bully them to change their testimony he will be in a fuddle for a long time.
He could even start with why the Commissioner moved away so abruptly. He could try finding him and questioning him to find an answer.
Dev just does not seem to have the instinct that Shakshi and Rajnath posess to go to the heart of the problem and come to a conclusion.