Billy Bob Thornton’s finally cutting ties with ex-wife Angelina Jolie -- TMZ has learned, he just sold the Beverly Hills mansion the two once occupied together ... for a boatload of money.The ex couple originally bought the 11,000 sq. ft. pad back in 2000 for only $3.75 million -- right after they got married -- but thanks to celeb realtor Kurt Rappaport, Billy Bob Thornton (BBT) just closed a deal to sell the place for more than double that amount ... $8 million.BBT had originally asked for $10 million, but with the market these days ... he was forced to lower his price. Still, an impressive take.As for the home -- previously owned by Slash -- its pretty badass. In addition to an in-home recording studio -- the Roxbury Drive estate also features 9 beds, 8 baths, a pool, a tennis court, a gym, a library ... AND FOUNTAINS.TMZ