Kourtney Kardashian and her partner Scott Disick are reportedly arguing over their son Reign.

The reality star took to Instagram on Thursday and introduced her third child with Scott by sharing a photo of the little boy. In the snap the three-month-old can be seen lying on a rug in a white babygrow looking directly at the camera.

“My little turtle dove angel baby boy Reign Aston Disick,” the 35-year-old wrote in the photo caption.

But it seems the couple, who have had a tumultuous relationship for a number of years, disagreed on how to share the first snap with the public.

“They were both initially considering going with a magazine offer, but after Reign was born they were on really different sides of the fence,” an insider told Radar Online. “Kourtney changed her mind and told Scott that she did not want to go with a tabloid because she felt like it was ‘selling her children.'”

The pair also have five-year-old son Mason and two-year-old daughter Penelope together. While they have shared photographs of their children before, Kourtney’s decision not to do so this time around supposedly angered Scott, causing a rift between them.

“Scott looks at everything like a business deal and is always looking for ways to cash in,” the source continued. “But Kourtney has enough money that she does not need to go and do this for a measly $1 million dollars. To her, that is pocket change.”

The pair are rumoured to already be under strain after Scott spent less than a week in a rehabilitation centre in Costa Rica last month to deal with his alcohol issues.