Now that he is 80 years old, Charles Manson’s hippie exterior has weathered. Once 5-foot-2, the gray-haired mass murderer is undoubtedly shorter today. He walks with a cane and smiles with a set of dingy dentures. The “X” — later turned into a swastika — that he carved into his forehead now fills the creases between his bushy eyebrows.

But such things don’t seem to matter to his dark-haired, doe-eyed 26-year-old girlfriend, who moved across the country as a teenager to be near the mastermind behind the 1969 “Helter Skelter” killings.

On Monday, the Associated Press reported that Manson and Afton Elaine Burton applied for a marriage license on Nov. 7. Although a wedding date hasn’t been set, Burton said she and Manson will be married next month in Corcoran State Prison, a male-only facility sandwiched between Bakersfield and Fresno atop a lake now sucked dry by the California heat. Burton said the two will likely be wed in an inmate visiting room inside the prison with no more than 10 guests permitted from the outside.

“Y’all can know that it’s true,” she told the AP. “It’s going to happen.”

“I love him,” she added. “I’m with him. There’s all kinds of things.”

Manson has always been unlucky in love. Between prison sentences, he married a hospital waitress named Rosalie Jean Willis in 1955 — and the two had a son, Charles Manson Jr., who committed suicide in the 1990s. A year after she divorced him, he married a prostitute named Leona Rae “Candy” Stevens in 1959 and had a second son. Stevens divorced him, too.

Last year, when Burton told Rolling Stone magazine about their upcoming nuptials, Manson denied it, saying: “That’s a bunch of garbage. You know that, man. That’s trash. We’re just playing that for public consumption.” When asked Monday about his previous comments, Burton said, “None of that’s true.”

California Department of Corrections spokesman Terry Thornton confirmed that the license had been sent to the prison.

A marriage between the two would be unconventional at best. Manson, who is serving a life sentence, is not allowed family visits — or conjugal visits — so it’s unclear when, or if, the marriage could be consummated. Still, Burton said the union will give her access, as his wife, to his most personal information — a way to help her to continue to work on his case.

“There’s certain things next of kin can do,” she told the AP.

Born to a teenage mother with a taste for alcohol, Manson spent his childhood bouncing between juvenile halls and reform schools.

“I’m not a person, have never been a person,” he told Rolling Stone last year. “I am an animal been raised a lifetime in cages.”

Vincent Bugliosi’s New York Times bestseller “Helter Skelter” chronicles Manson’s descent from the career criminal-turned-flower child to the madman who led a small cult called Manson’s “family” to kill seven people. On parole for forgery in the 1960s, Manson hit the hippie scene. He was a wanna-be rock star and ladies’ man. He befriended the Beach Boys’ Dennis Wilson and he had groupies — including Mary Brunner, Sandra Good, Susan Atkins and Lynette “Squeaky” Fromme, who attempted to assassinate President Ford.

On Aug. 9, 1969, Manson sent followers from his commune in California to a mansion in Benedict Canyon outside Los Angeles, where director Roman Polanski and his pregnant wife, actress Sharon Tate, lived. He ordered his clan to kill everyone in it “as gruesome as you can” and stage the scene to pin blame on the Black Panthers. They murdered Tate and four others. The next day, they murdered a married couple, Leno and Rosemary LaBianca.

In 1971, the killers were convicted and sentenced to death. Manson was charged with conspiracy to commit the murders and was also sentenced to death. His term was changed to life in prison during a brief stint in the 1970s when California abolished capital punishment. His next parole hearing is set for 2027. He would be 92.

For the past seven years, Burton has been leading a campaign to free him.

Burton first learned about Manson as a teenager when she read a quote from him: “Air is God, because without air, we do not exist.” She fell for his pro-Earth views, better known as “ATWA” (air, trees, water and animals) and started writing letters to him. She saved up a couple grand and, at 19, packed her bags and moved from her home in Illinois to California to be close to him. She seemingly became infatuated with the convicted killer and, possibly, he with her. He gave her the nickname “Star.”

“Star!” he told Rolling Stone. “She’s not a woman. She’s a star in the Milky Way!”

Burton has been fighting for Manson ever since. She runs Web sites supporting his cause: Release Charles Manson Now, and ATWA, among others.

“People can think I’m crazy,” she told Rolling Stone. “But they don’t know. This is what’s right for me. This is what I was born for.”

If Burton and Manson say “I do,” she will stand across from him, the “X” on her forehead matching his. It was a mark copied by his co-defendants and followers during the murder trial in the 1970s.

But who knows what would come of the union. As Manson has said, “Everything is constantly changing, man.”

“I’ve always been pretty truthful with myself, as much as I can be under the circumstances,” he told Rolling Stone. “But I’ll never tell on nobody, not even me, man, so that’s why I ain’t never told nobody what really happened back then. I can’t tell you right now. It wouldn’t work if I did tell you, because it would change by morning. … The mind is a universal thing. Charles Manson and Beethoven.”