Former Made In Chelsea star Millie, 26, and 32-year-old rapper Pro Green announced their separation in a joint statement yesterday and it has now been claimed they could not agree on when to have children.
Apparently, Professor Green - real name Stephen Manderson - was keen to start a family soon, while Millie did not feel ready to become a parent, and this caused huge tension between the couple.
A source told The Sun: "Kids became a big problem. Millie didn't want them any time soon and he did.
"It's really sad for Stephen because he's a lovely and sensitive guy who will make a great dad one day. They loved each other but would have these crazy explosive rows."
Millie and Professor Green tied the knot in a lavish ceremony in September 2013. The couple held their wedding at the exclusive Babington House in Somerset and were joined by many celebrity pals.
But since their romantic nuptials, they have begun to lead separate lives, with Pro Green admitting himself last month that he had barely spent any time with his wife since New Year.
The couple enjoyed a holiday to Italy together, but he told The Sun he and Millie were like "ships that pass in the night".
"You would have a day off and try and have the best day of your life. But then you'd just start arguing," he explained. "That is a relationship."
Pro Green added: "The best way is a balance and being really clever with the time you do have together and making the most of that."
The couple announced their split in a joint statement yesterday. They said: "It is with sadness and regret that we confirm our separation.
"It is a mutual decision, we still care deeply about each other and would like it to be known it is on amicable terms and we wish each other well."
The news came hours after Millie made a head-turning appearance at a charity fundraiser for the Naked Heart Foundation. Posing on the red carpet before reports broke, Millie was wearing her wedding ring.
Neither Millie or Professor Green have mentioned their split on social media.