The wealthy 18-year-old vocalist had become increasingly irritated with Johnson because he would spend nights at his mother's residence, refused to accompany her to London when she met with executives from Sony and, most recently, declined earlier this week to join her at a charity function at the University of Wales in Caerleon, the Sun said Thursday.
The pair had been together more than a year and had been thinking of buying their first home.
"It seems they just got bored with each other because they've been arguing for weeks," said a friend of Church.
"Kyle was unhappy that Charlotte expected him to go to everywhere she did. He just felt like a spare part.
He was even forced to give up his job as a trainee hotel manager because he was spending so much time with her. I think he just wanted his life back."
Charlotte dumped previous live-in lover Steven Johnson, 19, after the part-time model and rap disc jockey cheated on her.