Now everything is making sense to me...its gone like this...that rainy night...yash is getting falshes of Aarti ...in that night...its for sure...that yash and aarti have had some weeker momments ...that night...and for yash this is sin and betrayal...he is still not out of Arpita memmory and that is why he is taking this as "Paap" and he thinks he has betrayed arpita and that he does not deserve arpita and hence to punish himself he broke arpita's belongings...and that is why he wanna be away from aarti. He also said in front of all tht nor hom nor aarti can tell anyone as to what has happened...
It might have happened under some alcoholic influence that night...and that would have made aarti not remembering...i am sure that this has to be reason...
btw whatever it is...it will be out soon...as aarti hs given 1 day to ganeshji...so may be tom last thing or monday ...cat will be out of bag...