To further DQ's love language reference, I think Dev and Sona are speaking their own love languages exclusively, which is why their direct communication is so compromised. They are each treating their partner as they would like to be treated, without really listening for what the other needs at this sensitive moment.
Sona is annoyed at Dev's immature behaviour and is demanding a more adult response from him: Following me without my consent is not cool, and I understand this is because you are worried about the other night, but let us sit down and figure this out like rational adults so we can solve whatever is troubling you and move on. She is demanding adult behaviour from Dev because that is how she would like to be treated. As we saw in her mini-me, Soha, at the beginning of S2, Sona does not like to be treated like a child, and she said as much to Ishwari in yesterday's episode: so much care is appropriate for Soha, but not me. Sona takes the definition of being an adult very seriously, and takes great pride in her independence and her ability to remain in control in even the most adverse of situations.
At his best Dev as a partner totally gets this, so most of his acts of care come in indirect form so not to challenge this ideal that Sona holds so dear: a wordlessly placed bed-tea, getting Soha to convince her to take the day off, telling her he sent cars to pick her family up because he wanted to and not because they couldn't come on their own, getting her to share with him by saying he likes the sound of her voice... and most of all, little acts of endearment towards her family. That said, this is not what is happening right now because of Dev's own shaky emotional state, and therefore his inability to think beyond his own feelings.
Dev is smothering Sona with attention and care because deep down, that is what he is craving from her. Just take a look at his face when he woke up to Sona's kiss the morning after the incident, before she said she had to leave for work early. It was like he was drinking in the sight of her face, the sound of her voice, and the comfort of her presence, telling him to sleep in because he had been such a hero the night before. When Dev gets destabilised emotionally, he needs that extra dose of TLC to come back to normal.
Again, when Sona is at her best, she gives him just that. After he found about his mother's theft, she didn't hesitate to hold his hands, wipe the tears off of his face, and tell him how special he was. She prepped him to meet Riya with words of encouragement and then told him how brave he was for taking that step. Most recently, when he found out about Ishwari's job and she came to understand his reaction, she was extremely tender with him until he found it in himself to deal with the situation maturely. Even after he had reluctantly relented, when he wished Ishwari good luck for the day, she hugged him and said how proud she was. Unfortunately, in this case, by the time Sona realised why he was so deeply affected, she had unconsciously pushed him away because his behaviour had hit her most sensitive nerve. And I think it took her so long to realise because she has always underestimated her importance in his life -- I think/hope they are addressing that here.
On the surface, it looks like the Dev of the Khatri phase vs. the Sona of the remarriage phase, but what I love is that there are these pyaar-bhare undercurrents that are drawing them back towards each other. Dev hit a home run with that Bose family photo, and it was as though he was saying, I am angry at you over this issue, and I don't want to talk yet, but I still love you and want to make you happy. Sona's constant efforts to communicate with Dev, in turn, are slowly chipping away at this fiercely guarded mix of guilt, anger, and fear he has swirling around inside him. In fact, I think that is why Dev is indulging in the childish response of silent treatment -- he wants to see Sona go that extra mile to show how much she cares. Sona in turn, wants Dev to understand that this one mistake she made shouldn't disqualify her as a high-functioning adult. They tried and failed to communicate with each other in their own languages -- hopefully today, we'll see them embrace each other's.