So, I think Sid and Roshni are putting up an act by creating a drama. The reason for me believing it is that they went missing for some hours, then came back and had this fight. They could have planned something during that time. If they were together for so many hours, they would have cleared atleast some misunderstandingsš I don't think sid would try to rape her when they are alone, he would only make her understand if at all there was some confusion. So, I feel there is something more to what we have seen in this segment.
I think Sid knows everyone are against SidNi and would be continuously planning and plotting to keep them separated when they starts living together and create more problems for Roshni. So they may have made this plan to act like they hate each other, so that the villians can have some restš and by the time they could do something to solve the family misunderstandingsš I think it may go the 'meri aashiqui tum se hi way'
Or else Sid is really angry at Roshni and when they start living together she may find that she was wrong and may try to win back Sid. But I can't muster the courage to believe that Roshni calling sid rapist. So, I hope all this is SidNi planned dramaš Otherwise the entire beauty of SidNi relation may go down the drainš I'm scaredš