Grief is complicated.

When the person you're grieving is an ex-partner or someone you had an otherwise difficult relationship with, it can be even more complicated.

Right now, Kelly Clarkson is dealing with the death of her ex-husband, Brandon Blackstock. She and Blackstock, who share two children, made headlines over the years for their acrimonious divorce. In an interview with USA TODAY in 2023, Clarkson described the anger she felt from their split.

On Wednesday, Aug., 6, Clarkson announced she'd be stepping away from her Las Vegas residency amid Blackstock's illness. The next day, Blackstock's family released a statement announcing he died at age 48 after having "bravely battled cancer for more than three years."

Mental health experts say this news is an important reminder about the complex nature of grief. When someone you had a bad falling out with dies, it's crucial to understand that contradictory feelings are normal − and people's experiences are going to vary.

"You can hold two ideas at the same time," psychotherapist Stephanie Sarkis says. "One is, 'The way they treated me was not OK.' And also, 'I can feel sad for my kids that their father died at such a young age.' You could even feel sad because I wish he would've been a different person."

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Kelly Clarkson and grieving someone who caused you pain

Blackstock was the first-ever "American Idol" winner's longtime manager. The two tied the knot in October 2013 and finalized their divorce in March 2022. The details of their divorce repeatedly made headlines until its settlement. Clarkson was awarded primary custody of their children − daughter River Rose, 11, and son Remy Alexander, 9 − in November 2020. Blackstock also had another son Seth and daughter Savannah.

In 2023, Clarkson addressed her divorce from Blackstock in an interview with USA TODAY, speaking about her "anger" stemming from their split.

"I was very, very angry. I know a lot of people have gone through grief or a big tragedy like a divorce, and I know it’s a common thing, unfortunately," Clarkson said. "But there's nothing common when you’re going through it."

She added: "It's very foreign. It's horrible. A lot of time stupid, stupid (stuff) gets said, and you just can't believe it. I was angry and really hurt."

On Wednesday, Aug. 6, Clarkson released a statement on Instagram announcing she'd be stepping away from her Vegas residency amid Blackstock's illness.

"While I normally keep my personal life private, this past year, my children’s father has been ill and at this moment, I need to be fully present for them," she wrote about her Kelly Clarkson: Studio Sessions shows at The Colosseum at Caesars Palace. In the spring, the "Since U Been Gone" singer was also absent intermittently from "The Kelly Clarkson Show," though she didn't explain her absence in detail.

While grieving an ex-partner and co-parent, Sarkis recommends asking yourself: "What's the best way I can help my kids through this, while still acknowledging that this person did not treat me the way that I should have been treated?"

The shock of grief

When someone dies unexpectedly, their loved ones' world shifts. Without warning. Without time to process. What's left is substantial trauma.

Furthermore, behaviors around grief vary among individuals, communities and within family units. "How people grieve is influenced by the relationship they had with the person they lost, also what our religion taught us, what our culture taught us and what our family taught us," grief expert David Kessler previously told USA TODAY.

Shavonne Moore-Lobban previously told USA TODAY: "Youth and adults grieve differently based on the resources and developmental abilities that they each have. There are also gender-role stereotypes that impact people's understanding of how they are 'allowed' or expected to grieve and show emotion, based on what has been deemed 'acceptable' in society."

Regret is another powerful emotion that often accompanies grief.

"Even when the last interaction was positive, there can be regret that the last interaction may feel incomplete," Moore-Lobban said. "Of course, there can also be sadness and anger as a response to sudden loss. Both of those can be connected to a need to make sense of something that may feel nonsensical."

Contributing: David Oliver and Jay Stahl

This article originally appeared on USA TODAY: Kelly Clarkson, Brandon Blackstock and why grieving an ex can be so complicated

Reporting by Charles Trepany, USA TODAY / USA TODAY

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