"There was a time when I was jealous of people who were able to party," Demi reveals. "For instance, Miley -- in her music video 'Can't Stop,' her whole thing was partying and not giving a f**k. Part of me was super jealous that I couldn’t be like that. I had to look at my life and be like, 'Okay, that's just not what you can do. There's no need to be bitter about it.'"
The 22-year-old "Cool for the Summer" singer has often credited her boyfriend, 35-year-old Wilmer Valderrama, for keeping her on the right track, and shares that he didn't give up on their relationship even when he was advised to.
"We started dating when I turned 18 ... Right after that, I went to rehab," she shares. "People told him, 'You should probably leave. She's on a spiral, and you're going to be sucked down with it.' But he was like, 'I'm not leaving. This is somebody I really care about.' We relate on a lot of levels."
"I've seen a lot of s**t," she adds. "S**t people don't know about. He's seen a lot of stuff too."
And luckily for her, the former That '70s Show actor isn't the jealous type.
"Nick [Jonas] and Wilmer get along great -- Joe [Jonas] and Wilmer too," she says. "It's weird. In the beginning, I was like, 'Why the f**k are you friends with Joe [Demi's ex-boyfriend]?' He was like, 'He's a cool guy.' Yeah, I know. I dated him."
"There are a lot of girls in pop. They have badass lyrics, but I feel like I’m the only person other than Rihanna and Nicki Minaj who isn't afraid to say, 'Try something on me and I'll f**king beat your ass,'" Demi says bluntly. "There are people who can dress up and play the part, but their music doesn't say it."