"It is an insane amount of getting it out," the American Idol alum, 38, confessed.
Blackstock, 44, has put Clarkson through the emotional wringer: In November, he demanded $436,000 a month in child and spousal support. Even worse, Clarkson's former management firm — owned by her ex's father, Narvel, and where Blackstock served as her manager — sued her, claiming she owed them $1.4 million in unpaid commissions.
In her response, Clarkson countersued her ex's management company last October and accused Narvel and Blackstock of working as unlicensed California talent agents.
"Kelly feels duped — and like an utter fool," a friend shares with OK!. "She puts on a brave face for her talk show, but she's crying all the time."
The singer did score a victory last December when she was awarded primary custody of the couple's children, River Rose, 6, and Remington, 4, "but co-parenting with Brandon is no walk in the park," notes the pal.
In the meantime, she's leaning on her celeb friends, including Reba McEntire, Narvel's ex. "As Brandon's former stepmom, Reba has a rare insight into the situation," adds the pal. "She can see Kelly's really suffering."
The split seems to have also changed Clarkson's outlook on marriage — the talk show host recently revealed that she can no longer see herself walking down the aisle again.
"Coming from someone who's literally in the midst of divorce, I can't even imagine doing it again," Clarkson told guest Gwyneth Paltrow on a recent episode of The Kelly Clarkson Show. However, she insisted that she was happy Paltrow, 48, "found love and found the space and the vulnerability on that level to say yes and do it again."
But when it comes to the "Since U Been Gone" singer, she only has time for 'Me Time.' "I'm actually in that place where I think a lot of people, I've heard, that go through divorce [get to]," Clarkson said. "It's almost like you start dating yourself again, like you actually make time for you again."
She added, "I love dating me!"