Jake Owen

PHOTO CREDIT: Justin Wysong

Ladies, this is why you marry a musician.

When country star Jake Owen recently presented now-fiancé Lacey Buchanan with an engagement ring, “I told her, ‘The sparkle is never going to go away in that ring, and I don’t want our sparkle to ever go away either,’” he tells PEOPLE. “‘On your darkest days, I want you to look at it and see that there’s a glimmer of light in it. I want it to always remind you of the possibilities of our relationship.”

Owen, 30, designed the ring with Lizzy Raye Jewelers in Atlanta, and he had a classic look in mind. So the singer selected a 2.5-carat oval-cut diamond set in platinum with a “little bitty halo around it” and small diamonds on the band. “I want that ring to be timeless,” he says. “When my mom saw it, she said, ‘That looks like something Princess Diana would wear.’ I was so excited to give it to her.”

He got a lesson in diamond selection in the process, too. “I think the color is E color, E/SI1,” he says proudly. “I know all of it. No inclusions! You can always go bigger with less clarity, but with hers I really wanted it to be bright white, sparkling.

“I’m pretty spontaneous about a lot of things but that,” he continues, “look, she’s the most unique, amazing person I’ve ever met and I needed something on her finger just as unique as she is.”

Speaking of spontaneous, Owen’s proposal was exactly that.

He and Buchanan had talked about getting married, and Owen asked her father for permission, but on the day of his hometown show — at his old high school in Florida — “I only had one song left to play and it was ‘Don’t Think I Can’t Love You,’” he recalls. “I wrote it a long time ago about my family and my dad and mom had been married for 30 years. I just saw [Buchanan] out there, my family, and I was like, forget the ring, screw it, this is like the perfect place to do it.”

Even though he didn’t have the ring in hand just yet, Owen brought Buchanan, 22, on stage and proposed, making a joke about not having the rock yet, since it worked with his song lyrics. “The line in there is, ‘Girl, I can’t buy you a big diamond ring.’ So I kinda played it off as a joke. I was like, ‘But it’s coming, I promise.’”

An added bonus? “Because I asked her on stage, I have videos so we’ll always be able to relive that moment,” he says. “It seemed like it went by in an instant. I didn’t even remember if she said yes to me or not, it happened so fast! She had no idea. It was pretty cool to watch that happen.”

Owen hits the road this summer with Kenny Chesney and Tim McGraw on the Brothers of the Sun tour. And when he performs his new single, “The One That Got Away,” he’ll surely note the irony of the title. Offstage, “I got her,” he says happily. “She didn’t get away this time.”

–Rennie Dyball