Robert Duvall has seven decades as an actor under his belt and has made more than 85 films. He’s been married four times, divorced thrice and, he slyly admits, “I guess I can be convicted of all” the seven deadly sins — including “wrath over certain directors.”

Yet at 90 years old, the acclaimed star has shockingly few regrets. “He’s really achieved so much, and he’s proud of so many things he’s done, from his charitable work to winning the Oscar for [the 1983 film] Tender Mercies,” an insider exclusively tells Closer Weekly, who adds that, while he’s never had children, Robert has built a family with his wife of 15 years, Luciana Pedraza, 49. “He’s grateful for a lot, and tells his friends that he’s had an incredible life.”

That life could have gone very differently. The son of an amateur actress and a U.S. Navy rear admiral, Robert grew up in Annapolis, Maryland, but spent a lot of time on his uncle’s ranch in Montana — and maintains that if he hadn’t been bitten by the acting bug, he’d have been a cowboy. “I can’t remember stuff from two weeks ago sometimes, but I remember things specifically from my uncle’s ranch…when I was 12 or 13,” he says. “It was just terrific.”

Yet life had different plans for the big-screen natural, who, even at 4 years old, was wowing family members with his impersonations. After serving in the Army for a year after the Korean War, Robert moved to New York City, where he studied acting at the famed Neighborhood Playhouse — and became fast friends with fellow acting students Dustin Hoffman and Gene Hackman, whom he says once “offered me his last $300, which I didn’t take.” He still keeps in touch with both of them. “They went through the highs and lows together as struggling actors,” says the insider. “Fame didn’t change their friendship.”

AT HOME, AT LAST

Finding his soulmate took longer, however. Married to Barbara Benjamin Marcus from 1964 to 1975, Gail Youngs from 1982 to 1986, and Sharon Brophy from 1991 to 1995, Robert calls his failed marriages “part of the process of life,” and admits he might not have been the easiest person to get along with. “When I met my current wife — she’s much younger than I — we met in Argentina on the street, by chance,” says the actor, who wed Luciana in 2005. “I figured, why not? [And] it worked out.”

Indeed, while Robert continues to act in films (his latest, 12 Mighty Orphans, is slated to come out in June), his happiest times these days are spent far away from Hollywood, on the Virginia ranch he shares with Luciana. “One of their favorite pastimes is going on lengthy walks,” says the insider. “The ranch has a vegetable garden, a beautiful lake, horses and lots of wildlife. There’s so much land, you could get lost there. It’s given Robert a real sense of peace.”

– Alison Gaylin, with reporting by Natalie Posner