The 39-year-old country star broke his silence on the split during an appearance on The Bobby Bones Show. Shelton and Lambert announced they had filed to end their marriage in July, and the singer said the process was over in just days.
"In Oklahoma, it happens so fast," he shared. "Like, Miranda and I didn't have any kids, and we had a prenuptial agreement, whatever we had. Once we filed for divorce, it was over in, like, I think it was a nine or ten day waiting period."
"We knew if rumblings and rumors started coming out, they would just be that, because by the time anybody knew anything it was over, it was done," he recalled. "Our whole thing was, we are going to be cool about this, it is what it is. We're buddies."
Shelton and Lambert met at the CMT 100 Greatest Duets Concert in 2005, and married in May 2011. The couple collaborated several times during their marriage, including on several tours, and seemed poised to live happily ever after on their ranch in Tishomingo, Okla.
"This is not the future we envisioned," the pair said at the time of the split. "And it is with heavy hearts that we move forward separately. We are real people, with real lives, with real families, friends and colleagues. Therefore, we kindly ask for privacy and compassion concerning this very personal matter."
Shelton last released Bringing Back the Sunshine in September 2014, and returned as a coach on The Voice season 9 on Sept. 21. Lambert debuted her fifth studio album, Platinum, in June 2014, which topped the Billboard 200 and includes the single "Little Red Wagon."