Why did Sushant Rajput's girlfriend slap him publicly

It seems Sushant Singh is getting habituated of being slapped publically by his girlfirend. Not long ago his girlfriend had slapped him in a Yashraj party. Actually Sushant Singh cannot hold his drinks. He gets drunk very soon and often does some mistakes which irritates his girlfriend. This time also he got drunk in a party and started dancing with a female colleague. In due course he was getting closer and closer to her. This irked his girlfriend and she slapped him. The couple is in a relationship since last five years and will be getting married soon.