Katy Perry is reportedly all about "making tough choices" in 2014.

This year has already seen the singer split from her on/off boyfriend John Mayer for good, and apparently she is ready to make some other big decisions.

Katy has long been friends with Rihanna, but after hearing the Barbadian singer had been seen looking friendly with John at a Los Angeles nightspot she is now said to be rethinking things.

"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," a source told British magazine Heat.

"Katy's disgusted with her and is fed up of being hurt. This year is all about making tough choices that are best for her in the long run, even if they're painful. It's the last time she'll let Rihanna hurt her."

Although the pair were incredibly close for a time, they haven't been seen together as much of late. It's been suggested part of the issue is that Katy can't forgive Rihanna for missing her wedding to Russell Brand. They tied the knot in India in 2010 and although Rihanna organized the bachelorette party, she didn't make it to the big day.

"Rihanna has always been the dominant one in the friendship," an insider said. "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."

Last year, Katy hinted all was not right with the friendship during an interview with Elle magazine. Rihanna had been embroiled in controversy after rekindling her relationship with Chris Brown, who assaulted her in 2009, and Katy hinted she was unhappy with the situation.

"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," she said, widely tipped to be about Rihanna.