"I definitely feel like I'm sitting in the chair I'm supposed to be sitting in right now," the Maroon 5 singer, 35, tells PEOPLE of his upcoming wedding to Victoria's Secret model Behati Prinsloo. "It all feels very natural."
Wedding planning isn't the only thing keeping The Voice judge busy this summer – he is also making his big-screen debut as a rising singer-songwriter in the new romance Begin Again.
"I had a lot to prove, so I had to pretend like I knew what I was doing," he says. "I was also really busy, so I didn't have time to stew in my own insecurities."
Nor is he sweating his role as groom-to-be. When it comes to preparations for the nuptials, "I'm probably doing more than you think and less than you think, as well," says PEOPLE's reigning Sexiest Man Alive. "It won't be typical, I can tell you that."
As for his bachelor party, the Grammy winner describes it as "cool and mellow."
Seriously? "I think I've probably had enough bachelor parties for all of the bachelors in Southern California," he says. "In my lifetime I've done it right."
For much more with Adam Levine, pick up this week's issue of PEOPLE magazine, on newsstands Friday