if khushi knows why arnav married her, she will understand why he is doing what he is doing, she will also be more careful with shyam, she will realise that she should have tolf someone in the raizadas about shyam and her engagement.it will be the next step in their relationship.she will start thinking that there is lack of trust.if arnav doesnt trust her, somewhere it is her fault as well as she never told him about shyam.
if arnav finds that khushi is not guilty, he will stop treating her badly and try to win her over.he will also be more wary of shyam.he will repent that he didint trust khushi and may take some steps to improve their relationship.
in any case they story will move forward and viewers will also feel that the loopholes are being taken care of, so i think it will make a hige difference, although problems might always be there between arnav and khushi to keep the soap going for somemore time, as its on popular demand, we want to see arshi for a long long time.