"He said he regrets he didn't deal with the Chyna drama privately and said it wouldn't happen again. One thing Rob did not apologise for - he flatly denied he ever physically abused Chyna," a source told TMZ.
"Rob also acknowledged all of the Kardashian women warned him Chyna was 'bad news' and he should stay away - advice he ignored. He told them they were right."
During his sickening tirade, Rob also mocked his mother for trying to stop his unhinged tweeting.
"My mom keeps telling me to stop, but she was married to a dude named Caitlyn, so I'm def not listening to her," he tweeted, referring to Jenner's former partner, Caitlyn Jenner, who was previously known as Bruce Jenner.
Rob, 30, later deleted the tweet. According to TMZ, Rob's family accepted his apology.
Sources also told TMZ the sock designer stayed with Chyna, 29, for the sake of their eight-month-old daughter, Dream.
"He also said he stayed with Chyna longer than he should have because he grew up in a two-parent household and wanted the same for Dream," TMZ reported.
Chyna, real name Angela Renée White, alleged Rob physically abused her - claims the reality TV star has denied.
She was granted a restraining order against Rob, which bars him from coming within 91m of her or posting pics of her, her son King Cairo, four (with rapper ex Tyga), and baby Dream.
The former stripper told Us Weekly the revenge porn debacle won't stop her from sharing personal details on social media.
"I feel like the more I share, the more relatable I am," she said.
"I don't care how somebody looks at me or their feelings. I know how I am. I know how I treat my friends and family and kids and that's all I'm worried about. You have some people that's weak and you have some people that's strong. I consider myself a very strong person."