John Mayer reportedly wanted his relationship with Katy Perry to be "all about him".
The couple split last week, shortly after there had been rumours they were planning to tie the knot. Perry's intense work schedule has been blamed for the separation, although it's now been claimed John's temperament was part of the problem.
"John can be selfish - he sometimes wants everything to be about him. She'd had her tour planned for months but he wanted her to drop everything... when she needed to rehearse," an insider told British magazine Heat.
Perry is divorced from Russell Brand, who told her he was ending their marriage via text message just 14 months after they exchanged vows. She has hinted her work ethic was one of the problems in their relationship, with Russell choosing not to visit her while she was on her California Dreams Tour.
He also wanted to have children, but 29-year-old Perry didn't feel ready.
It seems this could also have been one of the issues with Mayer, 36.
"He wants her to be at home with him, planning for a family and living the relaxed life on his ranch, but she's not ready for all that yet and felt like he was getting at her all the time," the insider explained.
Perry previously discussed the role kids had in her split from Russell.
"[He] really wanted me to have children, and I knew I wasn't ready," she told Marie Claire magazine.
"I think it was a way of control. I think it was part of, 'If I have a kid, then I would have to sacrifice - I'd have to be home more.' I really wanted to, but I knew I wasn't ready for it."