Katy Perry and John Mayer's break up made the 'Roar' songstress feel betrayed and as per previous reports, the pain repeated for Perry's best friend, Rihanna, suddenly became close with Mayer.

Though the two female songstresses claim to be best of friends, the 'Diamonds' singer suddenly became friendly with Mayer that they even had fun in one of Los Angeles, California's prominent hotspots.

"It seems like such a low blow. Rihanna has been so negative about John, she's always told Katy he's not worth her tears. So to find out that Ri was being all friendly with him is incredibly hurtful. Katy sees it as a betrayal," claims one source to Heat magazine.

This is likewise the reason why Perry is "disgusted" and is "fed up of being hurt". In 2010, the two best friends likewise had a temporary falling apart when the Barbadian singer wasn't able to attend Perry's wedding with Brand in India.

Insiders claim that the friendship of the two might soon be over: "Rihanna has always been the dominant one in the friendship. Things only work if Katy lets her take charge. But lately it seems Katy hasn't been as accommodating so that's caused some drama."

In one of her interviews with Elle magazine, the 'Dark Horse' singer also hinted about her tiredness of some people's dramas: "I know a lot of people out there with the most detrimental entourages - they are the root of their demise. It's really unfortunate but you can't save these people. My days of celebrity saving are over."