Kevin Federline is asking for more child support from ex Britney Spears. The father of six claims he cannot make ends meet otherwise.

Three Times More Required

Federline, 40, shares two sons with Spears: 12-year-old Sean Preston and 11-year-old Jayden James. In court documents filed on Tuesday, he claimed he makes just less than one percent of what Spears does.

Federline claims he is earning $3,000 per month. He receives $20,000 in child support for Sean and Jayden. Compared to what Spears earns per year, which is more than $34,000,000, he claims it just isn't enough.

"We think the reasonable needs for the children while they would be in Kevin's custody is probably three times what he's currently receiving," claimed Federline's attorney, celebrity divorce lawyer Mark Vincent Kaplan, in a conversation with PEOPLE.

A source close to Spears told the magazine that Federline couldn't account for where the $20,000 per month he's currently receiving is going.

Breakdown In Negotiations

Federline filed a request to review the pop star's financial documents, to ascertain her net earnings. The child support hearing schedule will be held in August.

Kaplan's team approached Spears's camp to try to negotiate a voluntary increase but were ultimately unsuccessful.

"We're still hoping to resolve this without judicial intervention," advised Kaplan.

Two Very Different Worlds

The lawyer believes Federline is entitled to more child support as the lower earning parent. Otherwise, the standard of living will differ too greatly between the two households.

"Otherwise, you have a situation where when I go with Mom, I get to pick out what pony I wanna ride that day; when I go with Dad, my high point is mowing the lawn with him," he advised.

Federline claims in the documents that he cannot make a living from dancing anymore, due to his age, and that there isn't much demand for him as there was back in 2008. These circumstances affected his income negatively.

Trying To Move On

Federline and Spears reached their last official child support agreement back in 2007, around the same time her father took control of her financial assets.

Jamie Spears offered to make a budget for Federline when he originally asked for more child support. Kaplan did not accept it, suggesting Spears's interests were only in his daughter's financial situation, and not Federline's.

He divorced the iconic pop singer in 2007 after almost three years of marriage. Federline re-married in 2013, welcoming two daughters. The former rapper and dancer had two more children with ex-fiancée Shar Jackson.

Spears, meanwhile, is dating trainer and model Sam Asghari. She's in preparing to take her hugely successful Las Vegas show on tour later this summer.