Can't help but compare your fic with the serial, and I feel this track is so much better in your work! This Sheetal track on the serial was extremely irritating--not for the fact that they introduced a possible kid from Arnav's past (given his implied lifestyle and dating history till he met Khushi, Arnav having an unplanned kid of whom he had no knowledge of, was a possibility, even if unlikely). But they could have shown this track so meaningfully, bringing intensity and edginess, perhaps showing an awakening of Khushi's possessiveness and sense of ownership over her husband, instead of being a doormat all the time.
And they could have shown Arnav being initially irritated at Khushi doubting him, and then his pain when he realized that after all, he did the same thing with Khushi-- doubting her regarding Shyam, on far less 'proof' than what she was confronted with, in his case.
But on the show, we got to see a retrospective transformation of Arnav into a fun loving, sporty college jock, who seemed to have loved playing basketball with his ex, and also was considerate enough to lose to her, to make her feel good!! The CVs just conveniently forgot the back story of a tormented and bitter Arnav who could never really recover from the trauma of his parents' death. The man for whom winning was literally everything!!
It was also really odd how in the serial, despite knowing Khushi was having so many insecurities to the extent of getting a DNA test done, Arnav was still shown as reminiscing of 'awesome twosome' days with Sheetal, engaging in non stop banter with her ( to the extent where he himself felt awkward a couple of times).
So please, please do continue with your story and give us your take on Arnav's realization and how he makes amends. He needs to make Khushi realize how important & essential she is in his life...and that he adores her for the unpretentious, carefree and loving person that she is...