[oxy.raj]

Yeah, in the chapter where they discuss Tharun after pizza breakfast, they actually discuss this. Nikitha says something like just like Jay has sex with Anjali, she too will have sex with Tharun and when he says it's in the past, she says future will become past in the future or something like that. The main issue here I feel is not Jay witnessing sex or Nikitha telling Jay that she loves Tharun and Chose him , IIRC in that discussion he actually says if it's only sex then not a problem or something like that but warns her she will get hurt when Tharun uses her for lust. But we know that Tharun loves her and despite the way he behaves possessivly or not transparent about Mithra, Nikitha wants to build her future with Tharun despite as of now she having her heart with Jay. She chose that and she believes she was so wrong about Jay, she crossed so many lines and she is the one not deserving of Jay. 
As of now Jay also doesn't know about Tharun and Mithra. As far as I know he is aware that they were planning to get married next year. He didn't know the backstory of his breakup text.

My take is Jay will accept her if she says she loves him and made a mistake of not understanding his acts/feeling but what will make her think that she is worthy of Jay and they can have a life together going forward.

Also there are gaps like we don't know what Jay told Sharmi when they went to hospital for bandage removal. If he told everything, will Sharmila reveal that to Nikitha. She actually was very remorseful for her part and even offered herself. Will she interfere in this situation?

I guess Nikitha and jay won the UK/US trip but the proximity in the house/village didn't do anything so what will change on the trip, if it happens?

This has become too complex and too complicated to untangle.

What if Tharun and Jay will fly to US/Uk