The two have since tweeted their support for one another despite the former boy-bander painting their past relationship in a less than flattering light.
So why did the 24-year-old decide to spill the beans on growing up in front of the public eye?
"It was just something that is my story and my life and nothing that I necessarily felt like I could talk about before and it felt like the right timing and I just decided I would tell it all," he told E! News at a launch party for the latest issue of Nylon.
"There's this perception of a celebrity or if you do music that you have to be this person that's untouchable and I don't want to be that person. I'd rather be somebody who can be open and honest and people can get to know me and relate in some way, hopefully."
Jonas also explained that in an effort to ease the blow, he warned a few close friends and family before the magazine hit the stands.
"I had the opportunity to talk with Demi beforehand and a few other people in my family and obviously something like this is going to be jarring but Demi and I have a really strong friendship and I would obviously never want to hurt her." Awww!
And what did Demi have to say about that?
E! News also caught up with her on the red carpet for the event, since she graces the cover of the fashion publication, and dished with the X Factor mentor about all things Jonas.
"Well, first I was like, ‘Umm, we need to talk,' and then we talked and I was fine," she said while laughing.
"I was like, ‘Look, I'm not mad at you but you need to choose your words more carefully next time.'"
But in the end, Demi and all three of the Jonas brothers have such a close bond that they're more like family than friends.
"They're my brothers, I love them so much. Joe and I argue like brother and sister and [he's] always going to be in my life," she said. "He meant no harm and he's never had a chance to tell his side of the story so I'm proud of him."
But watch out, Joe!
"I also said beware because I'm writing my tell-all now." Demi revealed. "I have a memoir coming out probably next year, I don't know, whenever it's done!"