Katy Perry and John Mayer split up because of her upcoming world tour.
The 'Dark Horse' singer, 29, was reportedly dumped by the singer-songwriter, 32, because they were arguing a lot and she is "stressed" about her 'Prismatic' concerts, which are scheduled to kick off in Belfast, Northern Ireland in early May and will see her travel across three continents until the end of the year.
A source told UsMagazine.com: "She's stressed about the tour, they've been fighting. 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."
The duo, who released the romantic duet 'Who You Love' in December, first began dating in summer 2012 and had an on/off relationship until things became serious between them last year, after Katy publicly admitted she was "still madly in love with him."
A friend predicted they could reunite again, saying: "Not sure how long it will last this time but yes, it is off for now."
But a third source said: "They've had rough patches, but this may be for good."

Kanye West's daughter has "changed his life".
The 'Bound 2' singer - who has eight-month-old North with fiancee Kim Kardashian - says the youngster inspires him in everything he does.
Asked if she will inspire his songwriting on 'Late Night with Seth Meyers', he said: "Yeah, totally. Everything, and my approach to life. It's changed it."
Though Kanye, 36, insists his future music will be "kid-friendly", he insists he isn't going to change completely as he still wants to maintain his artistic integrity.
Discussing whether he will write "kid-friendly" tracks, he said: "I think artistic, intellectual kid-friendly songs. Meaning, like, you go to Europe there's nudity on TV.
"So it's all in the way you're raised and have an understanding and appreciation for what you're looking at, what you're hearing, and why you're hearing it. If you think about the 'Yeezus' album, cursing was definitely necessary. It would be like if you [asked] Quentin Tarantino, 'You going to make G-rated movies?' It's Quentin Tarantino!"
After the host praised Kanye for his ability to drop curse words during his performances on live TV, the rapper laughed and said: "Dropping cursing is the least of my worries creatively."

Ozzy Osbourne's granddaughter used to be "scared" of him.
The Black Sabbath rocker dotes on 22-month-old Pearl - the daughter of his son Jack and his wife Lisa Stelly - and though they have "fun" together, the youngster used to be nervous around him because of his long locks.
Jack said: "She was scared of him for a while because she had this weird thing about if you had long hair, so now that she's grown past that insecurity, she likes him.
"My dad is really enjoying being a grandpa, but I think what he enjoys most is that he can have fun and then when it's no longer fun, he can just hand her off."
Jack, 28, says his daughter is a "girly girl" who loves dressing up in her mother's clothes - particularly her underwear.
He told PEOPLE: "She likes putting on her mom's jewellery, walking around with handbags and she loves putting bras on.
"It's really funny. She'll go and grab one of her mom's bras and gets angry if you don't put it on her."
The former 'Adrenalin Junkie' host - who was diagnosed with multiple sclerosis (MS) just weeks after Pearl's birth in 2012 - adores the fact his daughter loves to give him hugs.
He said: "She's actually really hugging back -- a real deep hug -- and I like that. [She] wraps her arms around my neck and just gives me a good squeeze."

Lily Allen won't use her children as "accessories".
The 'Hard Out Here' hitmaker has daughters Ethel, two, and 14-month-old Marnie with husband Sam Cooper, and insists her girls are well looked after even though they're not spotted out much.
She wrote on Twitter: "good morning, i'm getting alot of nasty messages in my feed about my children. Thank you for your concern, but i assure you they are fine.
"and are never far away, you just don't see them in pictures because i don't tote them around like accessories. (sic)"
The 28-year-old star - who recently made her pop comeback following a four-year hiatus - admits she hasn't juggled her family life with the challenge of being on the road yet, but insists she'll make sure she finds time for her loved ones when she's on tour.
Lily previously explained: "I haven't done it yet [toured], so I don't know how I'm going to manage but I just try and spend as much time with them in the day time as possible, and then if I'm working at night, and vice versa."

Charlotte Church says Miley Cyrus has a "skewed perspective".
The 28-year-old singer - who was catapulted to the spotlight as a classical singer before branching into pop music in 2005 - can relate the young 'Wrecking Ball' hitmaker, 21, who made headlines last year for a number of provocative performances, and expects she will change her attitude in a few years.
Charlotte said: "It's so obvious this young lady has a skewed perspective because of what she's been through. All she knows is to sell and be sold. This sounds patronising but in a couple of years she'll change her tune. I went through a similar-ish thing, not to the depths she is taking it to.
"But it's exhibitionism. As a teenager, you're really egocentric. Why would you give a f**k about the rest of society."
Charlotte has two children - six-year-old Ruby and five-year-old Dexter with Gavin Henson - and although she is a fan of Katy Perry, she wouldn't want her daughter to look up to the musician, who is seen naked in her video for track 'California Gurls'.
She added to Stylist magazine: "I try to let my kids make their own way and be free, but trying to protect them and let them make their own choices at the same time [is hard]. For instance, I don't want my little girl to see a Katy Perry video. I like Katy Perry; she's funny - I'm not fussed on her music - but I don't want my little girl to hold her up as an ideal.
"I think a lot of what she does is marketed to children. All that candy stuff [in her 'California Gurls' video]. If [Ruby] had seen that she would have loved it, sweets everywhere and then there she is - this naked chick!"

Sweden's Princess Madeleine and Chris O'Neill have named their daughter Leonore Lilian Maria.
The six-day-old child's moniker Lillian, pays homage to the late Princess Lilian of Sweden who passed away aged 97 in March last year, while it's believed Maria may be in honour of Chris' mum Eva Maria.
The tiny tot's name is only held by 128 women in Sweden, according to national statistics, and royal expert Roger Lundgren agrees the name is an unusual choice.
He told Swedish newspaper, Aftonbladet: "It's definitely something new. There aren't many Swedish girls called Leonore."
The royal, who is fifth in line to the throne, will also be given the title of Duchess of Gotland, it was revealed at a meeting of the Cabinet Council held by King Carl XVI Gustaf and Princess Victoria on Wednesday (26.02.14).
Shortly after Princess Madeleine gave birth in New York on Thursday (20.02.14) her parents King Carl and Queen Silvia jetted to the United States to meet their granddaughter.
Speaking of the baby's arrival, they gushed: "We know today both happiness and warm thanks. Our joy is great. We wish now that Princess Madeleine and Christopher get peace and quiet and can take advantage of this unique time with her little daughter."
 

Steven Moffat says it would "insane" to remake 'Doctor Who' in other countries.
The BBC sci-fi drama's executive producer believes it would be misguided to attempt to create a foreign version of the show because there can only be one Doctor.
He told BBC News: "If anyone were to ask me, I'd say it's an absolutely insane idea. You couldn't have more than one Doctor Who in the world. It would just be dreadful."
Steven, who is also the brains behind BBC's hit Sherlock Holmes adaptation 'Sherlock', admitted that he only keeps British audiences in mind when making the shows, despite them being popular around the world too.
He explained: "'Sherlock' and 'Doctor Who' are both doing rather well but they couldn't be more definitively British. They're obtusely British. They're about as British as it gets. You shouldn't be afraid of being British because that's what you're selling."
The 52-year-old TV mogul addressed rival Sherlock show 'Elementary', which airs in the US, admitting he still hasn't seen an episode.
Steven was approached by American channel CBS to remake his version of 'Sherlock' but declined.
He said: "We declined, saying we weren't ready to do that. Shortly after that, they announced they were making an updated version of Sherlock Holmes. Those are the bald facts. I can't comment on how it turned out or the people that made it because I've never seen it.
"We don't own Sherlock Holmes. We don't even own the idea of updating Sherlock Holmes. That's been done before, several times actually. So there's no action to be taken."

Matthew Perry's new show 'The Odd Couple' has received an official pilot order from US network CBS.
The 'Friends' star - who has co-written, produced and stars in the remake of the 1965 Neil Simon Broadway play - was granted a script commitment by CBS last December and has now been given the thumbs up to film a pilot episode.
The classic comedy follows the relationship between two polar opposite roommates, Felix Unger and Oscar Madison.
Matthew will take on the role of the irresponsible Oscar, but the part of uptight Felix is still up for grabs.
The sitcom is being written by 'Frasier' writer Joe Keenan.
Matthew said: "Ever since seeing the movie 'The Odd Couple' when I was 10 years old, it has been a dream for me to play Oscar Madison.
"To be given the opportunity to develop a modern version of it for CBS has put a permanent smile across my face. Plus, I think it's time for me to be in front of a live audience again. I miss that. The search for Felix Ungar is on!"
Matthew has struggled in his attempts to make a TV comeback since 'Friends' ended in 2004.
His last three shows - 'Studio 60 on the Sunset Strip', 'Mr. Sunshine' and 'Go On' - were all cancelled after one season.
The actor recently reunited with his former 'Friends' wife Courteney Cox on her sitcom 'Cougar Town'.

Lacey Turner would rather be in 'EastEnders' than move to Hollywood.
The 25-year-old actress recently returned to her role as Stacey Branning in the BBC One soap and she admits some have questioned why she has decided to go back to the show after finding success in other acting roles.
Lacey said: "I get people saying, 'Why have you gone back there?' I say, 'Because I love it! It's right for me. Some people want to go off and make movies, I just want to make 'EastEnders'."
While Stacey has only just returned to Albert Square, the character will be taking some time off soon to film a full series of 'Our Girl', the one-off drama she starred in for BBC One last year.
However, Lacey insists 'EastEnders' is her full-time home and she has even decorated her dressing room to look exactly like it did before she quit the soap in 2010.
She told Inside Soap magazine: "I've got everything laid out exactly as it used to be. It's like the last three years didn't happen. I'm funny like that! I don't like change."

Scissor Sisters' Jakes Shears has written a "whole album's worth" of songs with Kylie Minogue.
The frontman and band mate Babydaddy worked with the 'Into The Blue' singer on her 2004 hit 'I Believe In You' and 2007 record 'Aphrodite' and claim there's a catalogue of songs which could be released.
Jake told Attitude magazine: "I love writing with her and always have. I'm really proud of all the songs I've written with her and I think someday I'm gonna, like, put together a Scissors-Kylie record.
"There's a whole album's worth of music. It's from over the years. There's some really cool stuff that no-one has heard. We could definitely put together a fun little album. Someday I'm gonna be shifty and leak it."
The 'Filthy/Gorgeous' hitmaker, 35, also praised the 45-year-old singer's writing and claims she is "a lot of fun in the studio" and the trio don't treat recording as work.
He continued: "She's a great writer and I love writing with her, she's great with lyrics. But it's just like playtime, you know. It feels like play, not work. It's just a nice time for us to hang out and be creative with each other."
Jake will also join 'The Voice' coach on the talent show on Saturday (01.03.14) to help advise this year's contestants.

Rudimental have collaborated with Beats by Dr. Dre.
The BRIT Award-winning drum'n'bass group are giving fans a unique look into the creative process behind their latest single, 'Powerless', which features vocals from Becky Hill.
The 'Waiting All Night' quartet feature in the first of a new YouTube series, 'Beat by Beat', which examines the sounds and elements used to create the track, and experience the song as the stars' intended when they were recording it.
In a unique innovation, fans of Rudimental - who won Best Single at last week's BRIT Awards and performed with Bastille - will be able to simultaneously play six different video clips on one page to create different sounds, giving the impression of a DJ's sound mixing desk.
Rudimental - consisting of Piers Agget, Kesi Dryden, Amir Amor and DJ Locksmith - recently revealed how they risked their careers by releasing the smash hit 'Waiting All Night'.
DJ Locksmith told BANG Showbiz: "Everyone was kind of against us putting it out there and all four of us came together and we put our careers on the line with 'Waiting All Night'. It got us through to where we are now, that's why it's such a special track for us."
Watch Rudimental's Beat by Beat video by visiting youtube.com/user/Officialbeatsbydrdre.

Pharrell Williams is streaming his new album 'G I R L' online for free.
The 'Get Lucky' hitmaker says he is "happy to share" an early preview of his second studio album, ahead of its official release on March 3, and all the tracks have been made available to listen to on iTunes radio.
Taking to Twitter, Pharrell wrote: "Thankful for the opportunity to share my new album with everyone. (sic)"
The ten-track follow-up to Pharrell's 2006 debut 'In My Mind' features his Oscar-nominated hit, 'Happy', along with a collaboration with Justin Timberlake on the track 'Brand New', while Alicia Keys teams up with the star for 'Know Who You Are'.
Pharrell, 40, worked with Miley Cyrus on her controversial '#Bangerz' album last year she has returned the favour by lending her vocals to his song 'Come Get It Bae'.
The album also sees a reunion between The Neptunes producer and French house duo Daft Punk following the success of their hit 'Get Lucky', which conquered the charts.
Speaking about the inspiration behind the album's title, Pharrell said: "Imagine if all of the talk show hosts in the world were women, all of the presidents were women, this is my gift to them. This album is dedicated to women across the world."

'G I R L' Tracklisting:
1. Marilyn Monroe
2. Brand New (feat. Justin Timberlake)
3. Hunter
4. Gush
5. Happy
6. Come Get It Bae (feat. Miley Cyrus)
7. Gust of Wind (feat. Daft Punk)
8. Lost Queen/Freq (feat. JoJo)
9. Know Who You Are (feat. Alicia Keys)
10. It Girl