I don't think Sameer thinks the rishta broke up because of him, or else he might not feel so glad. May be he is just happy that whatever the reason is it is over. He didn't ask anything from Naina. That means may be he is just happy that Sharad chapter is over. So if he learns the rishta was over because of Chacahji he will not feel sad. He is not that kind of over thinking guy...as far as we saw him. He is just a sweet boy who believes and trusts too easily and do what his heart tells him.
But yes! This time he looks more confident. He should be. Naina is already melting. The problem with her is ...she thinks more and does very little. If Sameer doesn't take an action he might lose Naina, after all she is the sis of Arjun. He should either go to Chachaji, as he seems like the only sensible man. Chachi bhi chalega as he has a bond with her too. Besides both Chacaha and Chachi are romantic ppl...they might understand Sameer. Sadly I am still not seeing any hope for Naina. đ