Anokhi doesn't have a past.
Shaurya is the first man to colour her.
On the other hand;
Shagun did apply colour on Shaurya but he surely gonna clean it of .Its only on the surface.Whereas Anokhi's colour resides deep in his soul.Now that he has been coloured in Anokhi's love ,kisi aur ke naam ka rang kaise chad sakta hai..
Shaurya can't and he shouldn't start afresh without loosening the baggage of past .His past isn't only a past but representation of his thoughts that Anokhi will dislike.He needs to wipe it first.Shagun's entry will make him introspect ,face his demons and thought process that was ingrained in him since childhood.He will have to choose between his first choice and his forever,which will in turn may change his view towards Astha