"I knew, like, [from the] honeymoon it wasn't going to work out," she said on Sunday's episode of "Watch What Happens Live."
Kardashian West, 36, split from the NBA basketball player in October 2011 after getting married Aug. 20, 2011, in a lavish Montecito, California, wedding that reportedly cost $10 million.
The "Keeping Up With the Kardashians" star said she felt internal pressure to get married to Humphries.
"I just thought, 'Holy s---, I’m 30 years old. I better get this together. I better get married,'" she explained.
"I think a lot of girls do go through that where they freak out in thinking they’re getting old and have to figure it out, and all their friends are having kids," Kardashian West continued. "And so it was more of that situation.”
The reality star is now married to rapper Kanye West. The couple, who wed in 2014 just one year after she officially divorced Humphries, 32, have two children together.
Kardashian West was also previously married to Damon Thomas. The two divorced in 2004.