Jenner told Oprah's Next Chapter that he has regrets about the couple's lavish Montecito wedding, which was followed 72 days later by Kardashian filing for divorce.
"We went so overboard on that. And the way it turned out and everything," he said. "At the time it was honest, it was love - I was all in, but it turned so quickly."
Jenner was also asked by Oprah Winfrey if he ever truly believed Humphries and Kardashian's marriage would last.
"I was hoping it would work," he answered.
Kardashian praised Humphries during her interview with Winfrey, saying that he is "a good person".
The reality star is currently dating rapper Kanye West.
Winfrey's interview with the Kardashians continues on this weekend's edition of Oprah's Next Chapter, airing Sunday at 9/8c on OWN.
Watch a preview for part two of Oprah Winfrey's interview with the Kardashians below: