the reason behind the betrayal of RK?

Hey guys,i knw that its just a show bt I kip thinking abt MB...worried actually...stil ct believe that RK can be so evil...bt I thk most of us wud agree nw that it is rly revenge...bt he does loves her a lot n ct live without her bt bcz of that 4 slaps n his ego,he wil not accept it...as Bittuji rightly said that he wil be left alone...wen he wil realize his mistake it wil be too late...