Reposting from the Den: My two cents:
MSK has always been possessive when it comes to Geet. But would you call it insecurity, old demons hiding in his closet, or plain possessiveness depends on the situation. I agree when MSK and Geet had not confessed their love to each other, more than insecurity it was him not knowing whether she belongs to him or not. The tailor scene before the wedding can also be looked at as him wanting to get close to his future wife.
But with respect to Dev, MSK has always been a bit insecure. Not Dev as Dev, but with respect to the unknown person who had been a part of Geet's life. A person whom Geet had loved unconditionally and had become one with mind, body and soul atleast from her side. When he was ready to make her confess that she desires him, Geet tells him that she was pregnant. The reaction of MSK that day was because she already belonged to somebody else. He understood her situation, fell in love with her and was ready to face the future with her. And what he gets to know at that moment was that the guy was none other than his own brother. If it was any other person who wouldn't be around them day in and day out, MSK would not have minded so much. But this person is as much a part of their everyday lives.
And he has seen how Dev made Geet better after the MC. Being human, I am sure he would have wondered if Geet would have even looked at him if her marriage with Dev was fine. Seeing how Dev is working towards making Geet understand MSK, maybe he feels that Geet might find Dev to be a better person that him. If that is not insecurity, what is?? And today when she entered into his room and started talking abt Dev, maybe he felt that she was listening to Dev again.
When MSK asked Geet 'What jadoo did this guy do to you that you forgave him' he was not questioning her fidelity or her character. He was questioning her ability to identify people. Remember this was the girl who was ready to go to Canada to meet this guy and punish him, and she had forgiven him. So MSK was insecure that maybe Dev had used his charms on convincing Geet to forgive him. MSK knows that he is a tough person to live with. If Dev can understand Geet, if Dev can make her smile after a tragedy, if Dev can behave in such a way that Geet can forget all what happened in the past and forgive him, wouldn't a guy like MSK who is a perfectionist in all that he does wonder what Dev is doing better and what he is not??
Dev needs a girl of his own, if not for anything else atleast to put MSK's fears to rest. MSK needs to believe that for Geet, Dev is just his brother and thus a member of their family and nothing else...... and for Dev, Geet is MSK's wife and nothing else. The day he understands that is the day he will breathe a sigh of relief. I am happy that the CVs are touching on this topic of MSK being insecure of Dev and Geet's relationship because it is inhuman to just accept things and not have an iota of doubt in a person's mind. MSK needs reassurance from Geet and that is what he will have to get!!