John Mayer 'Jealous Of Katy Perry's Friendship With Ex-Husband Russell Brand'

WENN/Splash News/WENN/Splash News/

Katy Perry reportedly dumped boyfriend John Mayer because of his wandering eye, but it would seem that even the lothario singer has insecurity issues of his own!

And the subject of his jealousy, according to reports, is Katy's ex-husband Russell Brand, who she has remained friends with - something that didn't sit too well with Mr Mayer!

According to reports, the singer - who, let's face it, has had his fair share of celebrity ladies in the last few years - was none to happy that Katy was still friendly with Brand, who she was married to for just over a year.

John Mayer 'Jealous Of Katy Perry's Friendship With Ex-Husband Russell Brand'John Mayer 'Jealous Of Katy Perry's Friendship With Ex-Husband Russell Brand'

John Mayer was reportedly unhappy that ex-girlfriend Katy Perry is still close to her ex-husband Russell Brand (AKM-GSI/Splash News)

And a source said Katy knew that John was fed up of comparisons between him and the British funnyman, which she used to her advantage.

"John and Katy together were like a volcano just about to go off," a source alleges to Radar Online. "Their relationship was incredibly volatile, stemming from the jealousy they both harbored deep inside."

The insider said Katy was constantly unhappy with John's blatant flirting with other women, even if she was standing by his side a! t the time - but she knew how to get her own back.

The source added: "She knew that she could push Johns buttons by comparing his flaws to what she saw was great in Russell, which he hated!

John Mayer 'Jealous Of Katy Perry's Friendship With Ex-Husband Russell Brand'John Mayer 'Jealous Of Katy Perry's Friendship With Ex-Husband Russell Brand'

Katy Perry is still close to the British comedian - something that reportedly irked Mayer (Splash News)

Katy and Russell still talk to one another, and that was another thing that irked John. Hes never been in a relationship where he wasnt the main focus all the time and it bothered him."

Katy and Russell met in 2009 while she filmed a cameo for Get Him To The Greek, which was later cut from the movie, but the couple started dating and got married in October 2010 in India, but were divorced just 14 months later.

Katy and John dated on-and-off since last summer but called time on their romance last month.

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