If Ridz is confused, Sid has added fuel to the fire of confusion. If he had not pushed Ridz towards armaan, not sent DP, congratulated armaan on gatting Ridz back, asking armaan to take good care of her....none of this would have happened.
One can't blame Armaan because as far as he knows, SR have signed the DP and Ridz still loves armaan
Armaan behaved like a man today and the fact Ridz was apologetic and trying to appease Sid is because she is guilty! NOT ARMAAN
She feels guilty that even though she is married, she was attracted to armaan...there is no doubt after the Lonavala scenes
As far as Ridz wanting to be with Sid....She stated clearly that she is not doing any favors to Sid, she is just with him because she is fulfilling her duty of being a wife. Did I hear her even say once : Sid, I want to be with you because I love you?????