Katy Perry and John Mayer split - again

Katy Perry and John Mayer have split up - again.

Rumors about a breakup have been circulating for weeks now, fueled on by Perry's trips to London and Milan without Mayer. However, it wasn't very long ago that the two were also the center of wedding speculations, with Perry previously seen wearing a large diamond ring at the Elle Style Awards.

Last November, a source told E! News that family and friends of both Perry and Mayer were supportive of their relationship and praying that they would get married. The insider said: "They are so perfect together."

Katy, 29 and John, 36, collaborated last August on the song called "Who You Love," off of Mayer's latest album "Paradise Valley," a year after they went public about their relationship. They broke up briefly but got back together, stronger than ever.

"He literally is a genius, as is evident from his songwriting," Perry told Billboard of Mayer last October. "I always tell him, 'Darling, you know I'm going to have to give your mind to science after you've passed, because we're going to have to understand how all these sparks work.' We'll be in bed, and he'll be doing the crossword puzzle. Every night, he tries to finish it in under 10 minutes. When he puts his mind to something, he really gets it done very well. I always ask for his help."

Just last month, the two were spotted at a Grammys after-party outing complete with Perry's entire family.

"Not sure how long it will last this time but yes, it is off for now," a source told Us Weekly.

According to another source, Perry's "Prismatic" world tour is partly to blame for the split.

"She's stressed about the tour; they've been fighting," the insider revealed. "It is probably for the best, because she is going to be on tour for forever. Of course this happens all the time, I can't keep track anymore. But for now they are done."

News about their break-up was first released by E! Online.