Originally posted by: -Tulips-
This is what I feel might have happened.
I don't think this show will ever show Yash and Pooja in grey shades or as negative characters.
PooSh might have felt guilty of cheating on their spouses so they decided that they will divorce them but not to marry each other and live a new life like how Adi assumed. They filed for divorce because they felt they were not worthy of staying with their spouses.
They may have thought that once the divorce papers will arrive, we'll tell everything about the affair to them. They will apologize and tell then to sign the papers. But later probably they realized that they can't live without their spouses so they decided to drop the idea.
Yash sent those papers to Zoya but Zoya didn't get them. Pooja too didn't get the guts to sign the papers. They may have thought fate is giving them another chance to be loyal to their partners.
I think that's why Pooja decides to throw the birthday party because she wanted to start their relationship afresh again.
Pooja and Yash may have decided to meet each other 1 last time in Mussoorie before bidding each other goodbye forever and also to wish each other good luck but fate had other plans for them. They couldn't live together but died together because it's actually AdiYa who were meant to be together. PooSh were just small chapters in AdiYa's lives.
These are my guesses. I agree though PooSh should have confessed to their spouses about their affair but either they didn't wanted to lose them or they thought AdiYa would be shattered.