As Kelly Clarkson has been navigating the unimaginable death of her ex-husband, Brandon Blackstock , , her children have always "come first."

"It has been draining, exhausting, emotional [and] devastating," a source exclusively tells Us Weekly of Blackstock's diagnosis and untimely passing.

News broke on Thursday, August 7, that Blackstock died at the age of 48 , after a private three-year battle with cancer.

"A big part of it was making her schedule available for transporting the children to visit Brandon, and all of the emotions that came with this difficult time," the insider tells Us, referring to her Kelly Clarkson Show 's recent hiatus . "Kelly is a workhorse. Hard work is all she knows. She hates disappointing people, truly. The thing that kept her going was kno

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