Outlets have more details of what may have prompted Demi Lovato to cancel her European tour with the Jonas Brothers and seek treatment/rehab after some kind of altercation with a backup dancer. Apparently it all went down in an airport and there are witnesses to the fight, along with news that Demi was also talking smack to Twilight star Ashley Greene, who happens to be dating Demi’s ex, Joe Jonas. Drama! Ashley subsequently tweeted some crap about “karma” and came across like she was gloating and being petty, which seems typical for her.

A source tells E! News that Demi Lovato has struggled with bulimia, and it is among one of her emotional and physical issues. Two years ago, photos surfaced of her with suspicious marks on her wrist while she attended Miley Cyrus’ birthday party. At the time, her rep tried to shoot down the notion that it was self-mutilation, blaming it on candy jewelry…

But family sources say Lovato has indeed cut herself in the past.

However, things came to a breaking point in recent months.

“On tour [this summer] they were calling her ‘Demi Drama,’ another insider with the Lovato-JoBros tour tells E! News.

“After she split with Joe, it was just a whole bunch of drama, very awkward. Everyone tried to be professional, but you could tell it was wearing down Demi. It was a taboo subject to bring up, but clearly she wasn’t over Joe.

“The [Jonas] boys got a break after the tour, but Demi went a nonstop promo campaign for Camp Rock 2 and was pushing the single for that movie. It really was too much ask of a girl that young. She just couldn’t handle it.”

“I think Demi has a lot of issues she is dealing with, but at the source of them all is a great deal of stress.”

But another source says there was even more to her weekend meltdown that saw her shut down her Twitter account and leave the JoBros tour in the middle of its South American swing.

At the airport in Peru on Saturday, Demi got into a scuffle with a backup dancer.

“She just lost it right at the airport in front of everyone,” says the source. “The [Jonases’] dad basically said right there, ‘That’s it. You’re going home.’ ”

Demi also made verbal threats to Joe’s new squeeze, Ashley Greene, who was at the airport as well and witnessed her meltdown, the source says.

Indeed, according to a someone close to the Lovato family, the airport altercation was the “catalyst” to Lovato deciding to “take responsibility” for her actions

[From E! Online]

HollywoodLife has a whole speculative story about how Joe carrying on with Ashley in public could have sent Demi over the edge. E! Online’s Ted Casbalanca agrees with that theory, and writes that Demi “never got over the split with Joe and was hurt by how fast he moved on.” When Joe and Demi were dating they tried to hide it but Joe has been seen all over the place with Ashley and I wouldn’t put it past her to be calling the paps. There have been stories about how Joe is supposedly jealous of Ashley’s Twilight kissing scenes, and Kaiser thinks Ashley is leaking those stories.

Meanwhile Demi’s dad told Radar that the pressures of Hollywood got to her, but it sounds like he hasn’t seen much of his daughter since he split with her mom when she was little. There was a blind item recently that many of you mentioned about a teen star doing coke and having sex at a party. It could have been Demi, it could have been someone else or it could have been made up. I don’t put much stock in those blind items. I can buy that Demi freaked out and scuffled with some girl and shouted something at Ashley. She’s 18 years old and sounds really troubled. Hopefully rehab/treatment will help her.