In the November 2016 issue of GQ, the Bad Santa 2 star reveals that differing lifestyle choices ultimately led to their 2003 divorce.
Jolie, then in her mid-20s, was named a U.N. Goodwill Ambassador in 2001, and over the next decade, would embark on more than 40 field missions to support refugees across the globe. Thornton, on the other hand, says he was more concerned with life at home.
"I never felt good enough for her," he tells the mag, adding that it was never his style to indulge in the perks of A-list coupledom.
Richard Burbridge exclusively for GQ
"I'm real uncomfortable around rich and important people," the 61-year-old explains. Instead, Thornton never felt pressure to change, because as he puts it, "I like how I am."
After their split, Billy Bob went on to marry his sixth wife, Connie Angland, with whom he shares a 12-year-old daughter named Bella. Jolie has six children of her own with ex Brad Pitt.
Three months before Billy Bob and Angelina separated, the two announced they had applied to adopt a child from Cambodia. Jolie ultimately proceeded with the process as a single parent, officially adopting Maddox, now 15, in March 2002.
Regardless of their breakup, Thornton says he and Jolie remain on good terms.
In fact, Thornton admits the former lovebirds catch up every two months, and when they do, it's as if no time has passed.
For more from Billy Bob, check out the November issue of GQ available on newsstands nationwide.