Brandon Blackstock Seeking $436K a Month in Spousal & Child Support in Kelly Clarkson Divorce: Source

Kelly Clarkson's ex-husband Brandon Blackstock is looking for a hefty amount of spousal and child support.

The music manager, 43, is seeking $436,000 in monthly spousal and child support after an L.A. County judge granted Clarkson primary physical custody of their children River Rose, 6, and Remington Alexander, 4, a source tells PEOPLE.

"Brandon's been equally unreasonable in his requests for child and spousal support, as well as attorney fees," the source says. "Kelly's offered to pay for all the kids' expenses, but Brandon seems to think he is entitled to and needs $301K in spousal support and $135K in child support per month."

If Blackstock's request remains, he'd receive more than $5.2 million per year.

"Additionally, he's already asked for $2M for attorney fees when he's the one driving up the cost of the divorce with seven attorneys just representing him alone," the source adds.

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A rep for Clarkson, 38, and an attorney for Blackstock did not immediately respond to a request for comment. Clarkson's attorney Laura Wasser hasn't commented.

The monetary request comes after Clarkson filed for divorce in June after seven years of marriage. (The divorce proceedings are ongoing.)

A source close to the family also tells PEOPLE that Clarkson is "pleased" by the custody ruling and that her priority is to protect her children.

"As Kelly has said, her first priority in all of this is to take care of the kids and all the hearts that are involved in this divorce," the second source says. "It's been a hard time for everyone, but Kelly's pleased with the court's ruling regarding custody."

"Divorce is hard and it gets tense for most couples going through it. But Kelly's primary focus is on doing the best she can to protect the kids," the source adds. "In this case, she had to fight for them since Brandon and his attorneys were making unreasonable requests."

RELATED: Kelly Clarkson Awarded Primary Physical Custody of Kids amid Brandon Blackstock Divorce

The source explains that Blackstock wanted the children to go "back and forth" from Los Angeles to Montana or reside in Montana even though L.A. has "undeniably been their home base."

In late October, the court found that the children "have not resided in Montana" and instead Blackstock must travel to L.A. to see the children at Clarkson's Woodvale residence for "visitation and parenting time." PEOPLE accessed the court documents on Monday.

The court also stated that "the level of conflict" between Clarkson and Blackstock had "increased" and that the former couple would have "a difficult time co-parenting due to issues of trust between them."

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Addressing the ongoing divorce proceedings on her The Kelly Clarkson Show, the "Stronger" singer said she didn't see the separation coming.

"Definitely didn't see anything coming that came, but what I'm dealing with is hard — it involves more than just my heart, it involves a lot of little hearts," she said on the show in September.

"We know the best thing here is to protect our children and their little hearts," she added then. "So I'm usually very open and I usually talk about everything but in this case I will talk a little bit here and there about how it affects me personally, but probably won't go too far into it because I'm a mama bear and my kids come first."