"We don't talk. It's been 8 weeks-ish. Things were good after the launch party, they were fine, it just didn't work out," the mother-of-three said on the reunion.
"No, I left. I threw a baby shower for his best friend and found out one of the girls that he cheated on me with was sitting next to me the whole time and I had no idea, and she did, and he did, and I sat there and didn't find out till the end so I was humiliated," she explained.
"The sad part is that I tried to keep him out of my story line for so long but he was affecting, our relationship was affecting all aspects of my life that it boiled over into Teen Mom," she said.
The show's co-host, Nessa, was shocked with the story.
Kailyn and Chris share one son together, 1-year-old Lux Russell.
Are you shocked to hear Kail split with Chris? Let us know your thoughts!