It looks like father abandonment issues triggered Rob Kardashian's downward spiral, as he saw Lamar Odom as a father figure. Losing his father, Rob, was tough on him, and "he never really got over it," according to TMZ.

"Rob thrived around Lamar, inspiring him to start a business and get in awesome shape. They became best friends, but Rob idolized him," the site reports.

Khloe, who is now separated from Odom after four years of marriage, opened up about the issues on "Keeping up with the Kardashians."

 "Rob has said, like, 'Being in that house, it was so dark, and it made me do dark things,'" she told stepbrother Brody Jenner.

When Odom left the house and cut the family off, Rob did not know how to handle it and felt betrayed.

"Rob went into a tailspin because he felt abandoned by the only person who measured up to his dad. And that's when Rob got deep into lean and other drugs, which resulted in a dramatic weight gain," a source told the publication.

Another source told Hollywood Life he is not thrilled about his family airing his dirty laundry on the show.

"Rob really resents that his entire family is capitalizing on his weight issues by talking about them on "Keeping up with the Kardashians." It's embarrassing enough, so much so that he's just isolating himself, especially from the family. He still talks to Khloe [Kardashian], but he just doesn't spend as much time with her because he wants to isolate himself," they alleged.

At this point in the series, we know he skipped out on the family trip to Thailand. Khloe takes this hard, while big sis Kim thinks he should toughen up, and momager Kris Jenner breaks down.

"I want to fix Rob. Sometimes you just can't. I have not not cried myself to sleep in so long, I don't even know what that's like. I go to bed every night worried about everybody and I'm sure Khloe's doing the same thing," she told Kim.

Are you surprised Rob feels abandoned by Lamar? Let us know why or why not below.