Ellen Pao explains how the affair she had at work led to her infamous gender discrimination lawsuit

The road to Ellen Pao's infamous gender discrimination suit against Kleiner Perkins began with a 2006 business trip.

Pao, then a junior partner at the Silicon Valley venture firm, was asked to take a trip to Germany with another partner, Ajit Nazre. It was there that he told Pao that he was having marital problems and suggested that he and Pao would make a good couple, Pao described in her upcoming book, "Reset."

While the pair didn't get together then, Nazre told Pao shortly afterward that he'd separated from his wife. He and Pao had a short-lived fling, but when she found out Nazre was actually still with his wife, she broke things off, Pao wrote.

In an excerpt of Pao's upcoming book, "Reset," published Monday by New York Magazine's "The Cut," Pao points to ending that affair as the catalyst for her eventual lawsuit against the firm.

Although she lost the suit, the story serves as a warning for anyone who dates a coworker.

After Pao ended the affair, Nazre grew hostile toward her and started excluding her from meetings, she asserts, and the situation didn't improve over time, even after Pao got married, had her first baby, and returned from maternity leave, she wrote.

"Not only was he blocking my work, he had been promoted to a position of even greater responsibility and was giving me negative reviews," Pao wrote. "I started to lodge formal complaints about him. In response, the firm suggested I transfer to the China office."

Kleiner strongly denied Pao's claims during the lawsuit. When another female partner came forward with similar allegations against Nazre, he was put on leave and eventually left the firm. Pao guesses he left with a hefty payout, perhaps as much as $10 million.

Pao sued Kleiner Perkins for $16 million in 2012 for lost wages and other opportunities, claiming that the firm denied her promotions and other opportunities because she was a woman. After filing her suit, Pao was asked to leave Kleiner as well, and was told it was due to performance issues.

Pao lost her suit on all four counts, but has since crusaded for diversity in the tech industry and recently founded Project Include, a nonprofit that aims to build "meaningful, enduring diversity and inclusion into tech companies."

She wrote that rather than accept millions from Kleiner for signing a non-disparagement contract, she chose not to sign so she could publicly share her version of events.

Kleiner Perkins did not immediately respond to Business Insider's request for comment.

Pao's book, "Reset: My Fight for Inclusion and Lasting Change," is due out September 19. You can read the rest of the excerpt on The Cut.