Katy Perry and John Mayer appear to have hit yet another speed bump in on-again, off-again relationship.

According to RadarOnline.com, the pair has once again split, with a source telling the website the couple's relationship simply can't withstand "the pressures of their careers." The source added even their brief reconciliation was more a case of convenience than anything else.

"Katy and John reconnected once she had a break in her Prismatic World Tour," the source alleged. "So, for those few months they had a great time, pretending that it would last -- and of course it didn't."

Yet another source told Radar that Mayer seemed to get "jealous" of all Perry's recent success, which included hosting the halftime show of the Super Bowl.

"The fact that he does not have anything major going on with his career is really starting to take a toll on their relationship," the source added. "Katy is at an all-time high. She is starting to give in to what everyone around her is saying, that maybe she is too good for him."

Some are even speculating that 30-year-old Perry may have already put it all behind her. Just last weekend, she was spotted hanging out with Mumford and Sons banjoist Winston Marshall in Berlin.

Perry and Mayer's latest attempt at reconciliation came about a year after they split after she allegedly caught him cheating.

"The reason they have split in the past is because Katy gets busy," a source told Radar. "John can't handle the lack of attention, and she can't handle the trust issues she has when she's so far away. So they've learned that it's better to just take a break when they can't be in the same place."

Mayer, 37, has also dated Taylor Swift, Jessica Simpson, Jennifer Love Hewitt, Minka Kelly and Jennifer Aniston.