[RCF]

She did not choose Desai on her own accord, she just stopped Krish from leaving when Desai asked her to kick Krish out of the house. We will never know what would have happened if Nidhi did not intervene. After Nidhi spilled the beans about Desai she had no choice but to go back to Krish. We can go by her actions in the last two episodes and she does not seem like a woman in mourning or in a bad mental state, she seemed to enjoy Desai's company. I think she was genuinely in love with Desai and had it not been for Nidhi, she would have been impregnated by Desai on their trip to Himachal. She was ceding to Desai's demands even after she was separated from her husband. She started the game by kissing Desai in the restaurant first without Krish's knowledge. 
Did she confess that? No? Did Krish ask her to fuck Desai in Hall. ? No. It has always been Meera's decision to get intimate with Desai, and in this series, she has not even involved Krish much. It was always a one-sided arrangement. She should have been the one who should have apologized, but in the end, the whole blame was put on Krish's head and his fantasies.

I seriously think the author got bored with the characters and decided to end the story prematurely.

The whole thing can be interpreted in multiple ways , i gave my thought process and thanks for putting out yours. I always feel like readers only read the event that they are interested in but they leave out the details in prior episodes which lead up to that event. Please focus on Krish and not Meera on prior episodes before the event in Hall, you will understand whom to blame for everything that has happened. Please do not pick incidents that show as Meera took initiative but read the couple's intention together prior to that and it will then seem to you that the decision is always taken by the couple together except Ashish in this part.

Anyways coming to the point , Meera asking Krish not to leave means she is welcoming him back in to her life or resigning to the fact that she is destined to be with him as she exactly puts it before telling Desai she cannot ask him to leave..that's my interpretation.