"I'm fortunate that I get to work with the person that I'm in the relationship with," the singer-actress, 17, tells PEOPLE. "Rather than being across the country and texting him, I can have him hold my hand when I'm tired."
Lovato and Jonas, 20, who stepped out publicly as a couple for the first time in March, met while filming Camp Rock. That pre-romance time, Lovato says, was pretty sweet, too.
"We weren't together at the time," she says. "So, it was just working with my best friend. It was awesome. And now that we're in a relationship, it's even better, because we may be tired, but we have each other to be there."
How psyched is Joe to have Demi on the tour, which kicks off July 27 in Dallas? "It's going to be really exciting," he says. "Touring with Demi is going to be a lot of fun. It'll be different this time, but it will be fun."