In fact what Sameer is doing is actually good for Naina in the context of she wanting to move on and get married according to her family's wishes.. If he either pretends or really falls in love with some one else and moves on her guilt will reduce and she will be slowly able to heal thinking that the breakup actually did not break Sameer. This is my personal experience. This break up pain hurts even after years and years. But there is one consolation that the other person has moved on too and is happy in his life. Even though the happiness or the love is not the same it is better than he taking sanyas or becoming an alcoholic or committing suicide, then she will not be able to forgive herself. In this show may be they might not touch this angle, this track might just be to make Naina jealous.
Totally my pov I donot see anything wrong in Sameer moving on and trying to love another girl. He cant be crying over this all his lifetime. He made the mistake of loving a girl who thinks he is second priority so at least now he should love a person who is not like Naina. Sunaina is perfect because her family and Sameer's family know each other and nothing similar to this break up is possible in future. Even if he doesn't feel for Sunaina like how he feels for Naina, slowly he might develop feelings for her too.
