I don't think Raghu will commit bigamy, but maybe it's just a symbolic act by Raghu to show Shivani that he is committed to marry Sumi. Even if he puts Sindor in Sumi's mang the marriage isn't legal right until all the rituals have been performed and that in front of a priest, correct me if I'm wrong. He wants to make Shivani realize that after the 3 month's he will divorce her and marry Sumi, but we know that won't happen Shivani won't let it. 😳