Kevin Federline in 2023; Britney Spears in 2018.Credit : John Salangsang/Shutterstock; J. Merritt/Getty

Kevin Federline claims his ex-wife Britney Spears, with whom he shares two children, cheated on him with a woman, according to an excerpt of his upcoming memoir shared by USA Today.

In his memoir You Thought You Knew, Federline, 47, writes about a challenging experience early on his relationship with the pop star when, he claims, he found her kissing a female dancer in Amsterdam while on tour.

Spears, 43, and Federline met in 2004. In his book, Federline writes that he and the “Toxic” hitmaker had gone out with some of her tour dancers and staff, including a woman who introduced the then-couple; after a night of dancing and drinking, the group returned to the hotel.

Federline writes that he found Spears in a hotel room, claiming the other woman, “was sitting on the edge of the bed. Britney stood between her legs, hands on her face, and they were (expletive) going at it. Full-on making out,” Federline writes, adding that he was “stunned,” according to USA Today.

According to Federline, the incident made him realize this wasn’t what he “signed up for,” and he writes that he began packing his suitcase and “wanted out” and planned to fly back to the U.S. before Spears apologized and swore it wouldn’t happen again.

Federline writes that he was looking for a monogamous relationship and set that boundary. He claims that moment was a “turning point” for their relationship, which ultimately brought them closer together.

A rep for Spears shared a statement with PEOPLE on Tuesday, Oct. 14, responding to Federline’s memoir and the allegations in it.

“With news from Kevin’s book breaking, once again he and others are profiting off her and sadly it comes after child support has ended with Kevin,” they told the publication. “All she cares about are her kids, Sean Preston and Jayden James, and their well-being during this sensationalism. She detailed her journey in her memoir.”

Federline and Spears married in 2004 and split two years later before finalizing their divorce in 2007. The pair share two sons Sean Preston, 20, and Jayden James, 19, who grew up largely in Federline’s custody. Spears spent 13 years in a conservatorship, under the control of her father Jamie Spears; the conservatorship was terminated by a judge in November 2021.

Cover art for ‘You Thought You Knew’ by Kevin Federline.Listenin

In a recent interview, Federline told The New York Times that he has “never” been “against Britney” and has tried to help his sons have a great relationship with their mom: “It’s hard because when I really reflect on everything that’s happened — my kids do not know the woman that I married … And I’ve spent two decades trying to bridge that gap.”

Federline’s memoir, You Thought You Knew, is out Oct. 21.