A new documentary about Patrick Swayze is celebrating the late actor's life, and also shedding light on some of Swayze's dark times.

Paramount Network's "I Am Patrick Swayze," which airs Aug. 18 (9 ET/PT), the anniversary of his birth, includes interviews from Swayze's co-stars, managers, brother Don Swayze and widow Lisa Niemi, who opens up about abuse her husband of more than 30 years experienced at the hands of his strict mother.

Patrick Swayze (nicknamed "Buddy") would dance in his mother Patsy's class. And she was tough on him, sometimes "very violent," Niemi says in the film.

Niemi recalls one incident in particular in "I Am Patrick Swayze" that Patrick told her about from his 18th birthday: Patsy "was laying into" Patrick when his dad Jesse "came downstairs, pulled her off of Buddy, and slammed her against the wall."

Niemi doesn't explicitly say whether that abuse was physical or verbal, but says that Jesse threatened to divorce Patsy if she harmed Patrick again.

"He always thought Mom was so strict and so hard on him, but the way I saw it she just used that to spur him on," Don Swayze recalls in the documentary. "He was everything to my mother."

Rob Lowe also discusses Swayze's mother in the documentary, saying that people could "tell that (Patsy) had all of her energy fixated on (Patrick), for better or for worse."

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"Patsy was an example of what happens in families in a cycle of abuse," says Niemi, adding that Patrick's mother said she endured abuse from her own mother.

In an interview with "People," Niemi adds that Patsy “never hit him after" the birthday incident, and they "came to have a much better relationship" until Patrick's death in 2009 of pancreatic cancer. His mother died four years later at age 86.

“I think she would say, ‘Well, you know, sometimes I could be strict, I’m that kind of a teacher,’ ” Niemi told People. “She was a complicated woman, intense and an amazing life force. Patrick absolutely loved and respected her.”