Josh Brolin Reveals in New Memoir That He Tried Acid at 13 And Once Got Stabbed Before Turning His Life Around (Exclusive)

"I would not want to be in my 20s again," says the actor, who's releasing his new memoir 'From Under the Truck'. "I have no interest in going backwards."

Josh Brolin has a bright future ahead after a gritty past.

The actor, 56, gets candid in upcoming memoir From Under the Truck about his experience with drugs and violence and spoke with PEOPLE about his journey for a story in this week's print issue.

In his book, out Nov. 19, the No Country for Old Men star recounted taking acid for the first time with his Cito Rats surfing group and getting stabbed on the street in Costa Rica in 2013 after being asked for a cigarette or money by a stranger.

Brolin wrote that he was "stabbed in the belly button," which ultimately saved his life. "The umbilical ligament is the densest ligament in the body and it slowed the knife down enough to stop it from hitting any vitals," he wrote.

During the harrowing experience, the actor and his wife Kathryn waiting outside their hotel and the for an ambulance. After she brought him his phone, he called his ex wife Alice Adair – the mother of his two eldest kids – to tell her what happened. "I know what to do, but you’ll be fine," she told him.

"She’ll talk to the kids about what I loved most about them, about what they meant to me, and how I know they’ll grow into a future that they can feel proud of, and not spiral into shame because of," he wrote.

Related: Steven Spielberg Shut Down Josh Brolin On This Piece of Goonies Feedback: ‘He Was Right’ (Exclusive) 

Now, Brolin lives a sober life after a 2013 interaction with his 99-year-old grandmother.

While appearing on Ted Danson and Woody Harrelson’s podcast Where Everybody Knows Your Name in September, the actor reflected on his last night drinking alcohol after telling them that he hit rock bottom and “far worse than [that]" at 15 years old.

As for his last drunken night, he recalled, "There was a hit and run at Del Taco" where he "woke up on the sidewalk."

"I didn't know where my car was, and it wasn't that rare," Brolin said. "That was just, you know, the 400th time that it happened."

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However, that night, the Marvel alum was supposed to pick up his brother so that they could go visit his grandmother, who "was on her deathbed." He continued, "Anyway, I woke up on the sidewalk, went inside. My brother called me. ‘Where are you?’ Picked him up, walked into that hospital eventually."

Upon walking into the hospital room, he said his grandmother "picked her head up and looked at me and smiled and that was it."

It was that interaction that inspired him to change for the better. "I was done. I said, 'If this woman could get through 99 years on life's terms, how dare me?' " Brolin explained. "I was 45 years old and I'd gotten away with a lot, been in jail nine times, done a little bit of whatever. So I thought, I wonder if I could do that half of life like that and then do this half of life like this. Then I get to live two lives and not just one."

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While speaking with PEOPLE in an exclusive interview for this week's print edition, Brolin reflected on his current life and long marriage to Kathryn, his wife of eight years.

"The only thing you can change is yourself," he says of the lessons he’s learned about love. "And drinking probably doesn’t help the relationship if you reacted to alcohol like I did."

Brolin, who is a father of four – Trevor Mansur, 36, and Eden, 29, whom he shares with Adair and daughters Westlyn Reign, 6, and Chapel Grace, 3, with Kathryn – says his current life "is more raw. More naked."

"The fear is still there, but I just don’t care about it as much. That’s the beauty of age, man. I would not want to be in my 20s again," he says. "I just have no interest in going backwards. As crazy as life makes me sometimes, and as frustrated as I get at myself, I’m really like, 'What a gift.' "

From Under the Truck comes out Nov. 19 and is available for preorder now, wherever books are sold.