The musician decided to end their relationship after a 20-minute row on the phone, reports The Mirror.
"She is so intent on getting married and having children, he felt hemmed in," said a source.
"After a 20-minute phone conversation, he just said, 'I can't take it any more', and hung up. Then he texted, 'That's it - the end'."
Earlier this week, Mayer confirmed the split, telling reporters that the couple had "different chemistry" and that he didn't want to "waste" Aniston's time.