A thought

Ok so we know Sid fears for Roshni's life as Shabnam tried to kill her but Sid took her spot instead. Because she had given a choice at the hill. She had said if you save Roshni you have to die. So come out as Sid is not a choice because Shabnam wants either of them out of pic. Since to her Sid had died or not in the picture, she won't be killing Roshni just going to try to ruin her life and kick her. So Sid is staying silent from all. However, now that "Raghu" is joining hands with Shabnam, I'm sure Roshni might ask him what he is doing? She might tell him, "I thought you would be on our side. Did you not say to me that once you take a hold of my hand you would never leave me. I guess I was wrong, you really are nothing like my Siddharth. Wait when he comes I will kick you out from my house and my life." She just goes on yelling at him for betraying her trust and faith that she had. She tries to leave but he grabs her hand and tells her, "Roshni ji, why are you not understanding? I'm not on Shabnam's side. I'm trying to trap her. If she thinks I'm on her side then she will share her misdeeds with me. Which then I can use against her." Roshni smiles and says, "I didn't know you were so smart. My Siddharth does weird and dangerous plans like this. Raghu be careful with her." Sid smiles and as she walks away he says to himself, "told her my plan but not who I am. Your Siddharth will come back to you my love. Need to trap Saali saheba first and kick her out forever."