When Rob Kardashian decided to skip out on Kim Kardashian and Kanye West's wedding, he broke the news to his sister via email, she told Watch What Happens Live host Andy Cohen on Tuesday.
"He sent me a long email the morning of, that he was going to leave," she told Cohen. "There was no fight. ... We didn't even have a conversation about it."
Kardashian – who insisted things between the two are fine now, calling her brother "one of my best friends" – said she put the incident on the back burner to focus on enjoying her over-the-top Italian nuptials.
"I said, 'You know what? This is my day. I'm not going to worry about it. I totally hope he's okay,' " Kardashian said of her reaction to his departure. "I totally understand that he wouldn't want to go and want to see a lot of people if he's feeling uncomfortable."
Although she expressed regret that Rob wasn't on hand to witness the important moment in her life, she's not willing to dwell on the past. "You can only pray and wish that someone would not miss out on more memories in life, because life is about memories, so fix the problem," she said bluntly.
Kardashian, who with West celebrated their daughter North's first birthday in June, has been busy working on losing what she believes are lingering pregnancy pounds.
And while she can empathize with Rob's weight issues, Kardashian said she refuses to sit back and let life pass her by.
"I'm definitely a tough-love kind of person. If I don't like something that is going on in my life, I change it," she said. "I don't sit and complain about it for a year. I'm just a different personality."
She added: "I try to encourage him, and once you just don't make that change for so long and it's not happening, I get frustrated. My patience runs out."