I think we must remember that karthik married vedika when he and everyone else believed naira was dead. If naira came back before the wedding,,..it’s highly unlikely the marriage would have happened. so now that naira is back and in front of him... and he obviously still loves her ..it’s hard for him to suppress it..he said the other day that relationships and circumstances and situations may change but love never changes.. now he married vedika and he had told her twice ..once at the hospital when KD was ill and the second time when vedika found him in his naira grieving room,.. that they can try to make the marriage work..So obviously he can’t just tell her to get lost now that his real love is back..so I think he’s going to be yearning and longing for naira until something cracks ..and vedika will have to witness it and be the one to release him from the marriage...unless their marriage is proved invAlid...but it’s been A while already so I don’t know if the legal issue is going to ever come up..