Just before Shannen Doherty went in for brain surgery, she discovered her husband's 2-year affair.

In January, Shannen Doherty underwent surgery to remove a brain tumour. Just before, she discovered her 11-year marriage was over.

The Charmed and Beverly Hills, 90210 star, 52, has been receiving treatment for cancer over the last eight years, and documenting a lot of the experience publicly. She underwent surgery and radiation on her brain during the same month she and husband Kurt Iswarienko separated.

The couple cited "irreconcilable differences" in their divorce filing, but launching her new podcast Let's Be Clear with Shannen Doherty, Doherty shared how she found out Iswarienko was having a two-year affair.

Watch: Shannen Doherty reflects on her stage four diagnosis after Luke Perry's death. Post continues below video.

"I went into that surgery early in the morning and I went in after I found out that my marriage was essentially over, that my husband had been carrying on an affair for two years," she said. 

"To not go in that surgery, even though, being very clear, he wanted to go, I couldn't go into that surgery with him there. I felt so betrayed."

Instead, she was supported by her mother, brother and best friends.

"At the end of the day, I just felt so incredibly unloved by someone I was with for 14 years, by someone I loved with all my heart," she said.

She said she became "obsessed" with finding out the truth of the affair 

"If you share 14 years together and you cheated, doesn't that person deserve the absolute truth regardless of how much that hurts them?" she said, adding that she "also spoke to the girlfriend of two years that he cheated on me with".

She said she felt embarrassed by the whole thing.

"I also take some responsibility for the demise of our marriage — actually that's not true. Let me rephrase that, I do not take responsibility for the demise of our marriage, I take responsibility for some of the issues in our marriage," she explained. "I take responsibility not only because of how I was but because of how cancer impacted my marriage and how it impacted him the second time around."

After separating from Iswarienko in January, Doherty filed for divorce in April. Around the same time, her publicist  Leslie Sloane released a statement claiming Iswarienko's agent was "intimately" involved in their decision to divorce.

"Divorce is the last thing Shannen wanted," Sloane told Page Six.

"Unfortunately, she felt she was left with no other option. You can contact Kurt's agent, Collier Grimm at PICTUREKID as she is intimately involved."

Doherty was first diagnosed with breast cancer in 2015, before revealing in February 2020 that she had been diagnosed with Stage 4 breast cancer. In June, she then shared that the cancer had also spread to her brain. In her latest update in late November 2023, she said it had spread to her bones.

"There was a lump, and I had a mammogram and then a biopsy," she told Health Magazine in February 2019 of when she first learned the news. "When I got the results, I was in the car with my mum and I just knew. The longer I sat, the more it started sinking in. Then I started crying. I called my husband and told him. And from there, I just put together a team." 

Doherty was previously married to Ashley Hamilton from 1993 to 1994, and Rick Salomon from 2002 to 2003.

Feature image: Instagram.