Teigen said she was feeling "insecure" when she and Legend got into it at Kardashian and West's lavish nuptials in May 2014.
"It was a major blowout to the point where every time I see them I feel like apologizing for it," Teigen said. "I think I was really intimidated. I think it came from a lot of insecurity and I took it out on John."
"It was a lot of fabulous, amazing people in one room," she explained. "I was just very insecure -- I think that's where it stemmed from. You know how things snowball into a bigger thing? And also drinking, that doesn't help."
Teigen previously mentioned her fight with Legend in an interview with Kardashian on the reality star's app in July 2016.
"John and I got in the biggest fight at Kim and Kanye's wedding... That you've ever seen in your whole life," she said.
Kardashian said she also got into a fight with West during Teigen and Legend's wedding.
"Wait, I got in a fight with Kanye during your wedding," the reality star said. "I didn't go... [North] was just born and I was so fat, and I had nothing to wear so he kept texting me, 'Babe, this is the most beautiful wedding.'"
"We got into the biggest fight," she shared. "[I was like], 'Just stop texting me. Go enjoy the wedding. You're making me feel so bad!'"
Teigen and Legend married in September 2013 and are parents to two children, 2-year-old daughter Luna and 8-month-old son Miles. Teigen praised Legend on his birthday in December, calling him "the most incredible man."