Well, after watching yesterday's episode, I feel it doesn't matter who Riddhima chooses after all. I am a die heart fan of AR and would really like them to be together for eternity and I realised, that is what we're getting! It doesn't matter if Riddhima chooses Sid over Armaan to spend her entire life. There was, is and will always be love in her heart for Armaan. From yesterday's episode, you could see how they easily understood each other's problems, sacrificed their beautiful relationship for a bond that in society is higher above. But in this case, I felt Armaan and Riddhima had moved onto a new level in their relationship. They went above literal love, they had the silent understanding between them which is true love.
One example I can only think of right now is the relationship between Prerna and Anurag in Kasautii Zindagi Kay. They loved each other more than anything else in the world. Yes, they did get married but then parted ways. Prerna was then happy with Mr. Bajaj in her life but somewhere, sometime, she would always need Anurag. He was THAT part of her that was permanent. They were like ONE being. They may look different but in the end, they did come together, even if it was only after dying.
Similarly, Riddhima and Armaan just cannot be separated. Yes, she's married now but Armaan will always, always be that part of her life which she will never forget, she CAN'T forget. For the world, she will keep her relation with Sid, she will put in her best efforts to maintain it. However, deep down, even she knows that without Armaan she cannot exist. Armaan and Riddhima will ALWAYS love each other even though they can't be together.
It's like Kal Ho Naa Ho, Naina (Priety) and Aman (Shahrukh) couldn't be together, yet they just couldn't stop loving each other. Siddhant is like Rohit (Saif). He has to learn to accept that Riddhima's first love and only love will always be Armaan. Riddhima loves Sid too, but like a companion. A companion who SHOULD be friends with her first, THEN love her. Riddhima and Armaan are SOUL mates while Siddhant and Riddhima are just life partners. Instead of getting angry at Riddhima, Sid should understand her situation and take her hand and move ahead in life always remembering that BECAUSE of Armaan's sacrifice and love for Riddhima, he has her now.
In the end it will be AR :) It was, is and will always be Armaan and Riddhima together.