I was watching yesterday's episode and one thing came to my mind.I thought I will share with you all.
In the beginning of the episode where sid is making arrangements for the date,the first scene shown was sid talking infront of the camera (he is facing us) about the date.Suddenly I have a feeling that he had kept cameras in the tent to capture his and ridhima's date.
So.if there is a camera,it will have captured the intimate scene between Armaan and Ridhima.Sid may have seen that what all happened there.
Another possibility is the bracelet he gave was broken and the beads were on the floor.So he may understood that something happened there.Also Ridhima's weird behaviour would have confused him.
In the precap sid said that his eyes and ears are open.So I think that he knew what happened between AR before they were telling.
What say guys?