Sid is trapped badly by Simran, but reality is at that time he does't have any other choice but to Sign in the divorce paper, otherwise roshni's family would have been on road. And I have feeling that DD and Raj will be the last people to know about the truth as roshni will be hiding it from DD and Sid is bound by his promise. DD will never accept anything that is given to her, because her ego will be hurt and so if she found out that it is all because of Sid's Sacrifice then she in her anger will never accept it. And I feel that because of her ego problem she will not accept Sid for doing this to her daughter.
As per Misha I feel that she is taking revenge on Sid as he didn't marry her in first place or may be someone else is also involve in it.
@bold- In epi 228 Sid broke his commitment to Simran because he said he doesn't have any reason. Even after divorce that nutcase is still trying to separate Roshni from him. He also told her she can keep trying her best to separate Roshni from him. He will try his best to bring Roshni back as his wife in their house. Even then if she has any problems, he can take care of Roshni by himself, telling her he might also even leave the house with Roshni. Sid will not hide it anymore but if Roshni tells him to do so then that's different. But I think she will also want her mom to know the sacrifice Sid did for them because she loves Sid and cant see him getting insult everyday for the divorce. Now everything depends on Roshni, if she will open her mouth or not. But I do want to see an emotional SidNi scene after finding out the truth.