One thing Kunal had hard time accepting Siddhi in his life. Slowly he had come to start trusting her a bit & also felt he may have started to understand her resulting in him respecting Siddhi. Before their marriage, Kunal thought Siddhi is no different from Richa. Scares from Richa had not been healed yet.
When he came to know about Siddhi recommending Kunal, first it hurt his ego that & compromised his senses a bit. Richa aware of his nature later pounded on that there is rumor in office & legal community that only reason Kunal has job & his case is grace of Siddhi, implying this what Siddhi thinks of you. So that once again made Kunal think that Siddhi is no different from Richa & he has just began to think otherwise. Kunal's ego had always restrained him from taking help from others. One reason being taking help was to make compromise. Siddhi helping Kunal brought back feelings from his break up with Richa where she questioned Kunal how is he really going to provide her lifestyle given his damn principles. Siddhi first refusing the job & giving it to Kunal once again made him feel the way he did at that time. So with that in mind Kunal reinterpreted what had taken place with grievences of the past.
When Kunal was making Siddhi move around him, he was implying how he felt that Siddhi made him dance on her tune & twisting her arm a little was to finally tell he was very much hurt by her behavior.
One reason he was so much hurt was that Siddhi is his wife. As seen in the conversation followed by dance he says everyone is congratulating me but my own wife thought I am not good enough to do things on my own. So much for saying marriage was just compromise yet both were truly hurt by each other's behavior then. 😉
As silambu already pointed out that Kunal did regret his behavior seen by him remembering that dance. But Kunal was really hurt that person he finally started to trust, respect & understand thinks he's not good enough. We are hurt mist when our loved ones or those who we consider close to us.
Kunal definitely was rude & bit harsh, misbehaving depends on your perception. Not saying what he did wad right or justified, but I personally understand. One factor of his evolution is accepting that he does need help.