'How did I mess that up?': Matt Damon talks 'Stillwater,' parenting and writing again with Ben Affleck

Matt Damon is so surrounded by women in his life that it takes a visiting nephew making a comment about the all-female vibe for him to notice.

“I am quite regularly the only man in a room, and I don't even think about it anymore,” says Damon, who has three daughters – Isabella, 15, Gia, 12, and Stella, 10 – with wife Luciana Barroso, as well as 23-year-old stepdaughter Alexia.

As a father, Damon could relate deeply to playing a dad doing his best in a bad situation in director Tom McCarthy’s thriller “Stillwater” (in theaters now). His character, Bill Baker, is a former Oklahoma oil roughneck who, after struggling with drugs and alcohol in his past, desperately tries to help his estranged daughter, Allison (Abigail Breslin).

Convicted of murdering her girlfriend in Marseille, France, and serving a nine-year sentence, Allison always claimed innocence and now has a possible lead on the actual killer. Bill moves overseas to help and strikes up a relationship with theater actress Virginie (Camille Cottin) and her 8-year-old daughter, Maya (Lilou Siauvaud).

Damon says he found it “very easy” to access the pain and grief Bill feels as a parent: “Imagine carrying the guilt and shame of years of addiction and feeling like you failed that person and then feeling responsible for where they find themselves in their life. That would be a nightmare scenario.”

As hard as Bill tries, he can’t help messing up, and that’s also relatable for Damon, 50. “Everyone knows that feeling when you go and put your head down on the pillow at the end of the day and you're like, ‘Man, how did I mess that up so bad?’” he says, laughing. “That's part of parenting. We gotta go easy on ourselves, too, sometimes. It doesn't come with a manual. We didn't take a class. We're all doing the best we can and winging it.”

The 'Stillwater' star aimed for Oklahoma roughneck authenticity

“Stillwater" also addresses the country's political divide: Bill is an unapologetic, tattooed red state American, though he's introduced to a bigger world view.

“Ideally, you spend a couple hours with this guy and you understand that he's had a tough life and he's made mistakes, but I hope you feel empathy for him,” Damon says. “I certainly did.”

McCarthy and Damon traveled to Oklahoma to spend time with real roughnecks, and McCarthy once made the “ridiculous” mistake of ordering a yogurt parfait.

“To this day, these guys still give me (grief)," he says. "Most people are way more dimensional than we give them credit for at first glance. They're roughnecks, they're farmers, they're family men, and they're really curious people."

During their meetings, the locals also very quickly got over the “Matt Damon” of it all. One ribbed Damon about “Promised Land,” a 2012 film he and John Krasinski wrote about fracking.

“He goes, ‘Boy, I hope I like this oil movie better than the last one you did,’" Damon says, laughing. “What binds us is so much greater than what divides us."

Damon wanted to reflect such real-life interactions in Bill’s taciturn nature, which humorously contrasts with the chatty Virginie during car rides. On real-life road trips, Damon can be a talker.

“If you get me going on something, I don't shut up,” the actor says. Unless he's with a bud: He recalls a time when he didn’t love to fly and often drove cross-country with longtime friend Ben Affleck.

“There was always one part of the trip where we'd turn and go: 'Did we say anything to each other that state? Did we talk in Nebraska? I don't think we did,'" he says, "But when you know someone really well, it's that level of comfort."

Matt Damon re-teams with Ben Affleck on 'Last Duel'

For the first time since winning an Oscar for 1997’s “Good Will Hunting,” Damon and Affleck teamed up again as screenwriters for director Ridley Scott’s “The Last Duel” (in theaters Oct. 15). Set in 14th-century France during the Hundred Years' War, the medieval drama stars Damon as an accomplished knight, Jodie Comer as his wife and Adam Driver is the knight’s friend-turned rival she accuses of a vicious assault. (Nicole Holofcener joined Damon and Affleck's screenwriting team for the drama, which is told through both male and female perspectives.)

“I loved it,” Damon says of reteaming with Affleck. “We hadn't written together in 25 years, in large part because it seemed like such a daunting task. ‘Good Will Hunting’ took us so long because we didn't really understand structure. We understood the characters and we'd put them in different situations, but they didn't necessarily cohere into one narrative. We ended up with thousands of pages of different scenes, and then we just kind of mashed them together and made ‘Good Will Hunting’ out of it.”

With “Last Duel,” though, “it went really fast. So it made us feel like, 'Oh, let's write some more stuff (now).'”

In the period film, Damon rocks an extreme, gnarly long beard. The women in his life made it known they aren't particularly fond of his "Last Duel" makeover – or his Oklahoman goatee in "Stillwater."

"My wife doesn’t like a goatee and I like a goatee," Damon says. "So that look was particularly irksome to her. But the chin mullet and facial scars were taking it to another level, definitely."

This article originally appeared on USA TODAY: 'Stillwater' movie: Matt Damon on parenting, Ben Affleck reunion