Willie Nelson is winding down his 90th birthday year with a reflective look at this life.

In his four-part docuseries, "Willie Nelson & Family," available on Paramount+, Nelson looks back on the highs and lows of his life and career.

"It's hard to believe it was 60 years ago I wrote a song, ‘Funny How Time Slips Away,’" Nelson says in the series' final episode. "I was only 27, and I really didn’t know what I was talking about."

He noted that he plans to never stop, saying, "Right now, we’re on the road again. I’m not sure how many gigs we’ve played so far, but it’s a whole bunch, and we don’t seem to be slowing down."

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"Music provided and protected as the bus rolls down the highway," he added.

Read on for the biggest revelations from Nelson’s 90 years of life and seven-decade career.

Nelson met his first wife, Martha Jewel Matthews, in 1952, and he vividly remembers their first encounter.

"One day, I pulled up to a burger joint where a carhop in a halter top and cutoff jeans came to take our order. She was a dark-haired beauty, a full-blooded Cherokee. Her eyes set my soul on fire, and her name was Martha Jewel," he said.

Shortly after that, Nelson and Matthews began dating and then got married without her parents' knowledge.

"My mother didn't want me to marry because I was as young as I was, so we just ran off," Matthews, who died of liver failure in 1989, says in a voice-over.

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The couple had three children, Lana, Susie and Billy.

Lana recalled her mother comparing their relationship to the infamous Bonnie and Clyde as they struggled to make ends meet, "going through America on their own, not worrying about money but having to worry about money at the same time."

Nelson also recalled the ups and downs of their relationship.

"We had a lot of fun together, but we fought, and we both were drinking a lot in those days," Nelson said. "One morning we got in this argument, and she picked up this fork and threw it across the table, and it stuck in my side. It sounded like a tuning fork."

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As Nelson struggled to find success in the early 1960s, he left Texas for Nashville with Matthews and their children. But their volatile relationship and financial struggles put a strain on the couple, and Nelson found himself in dark times.

"She and I were fighting worse than ever, and I started drinking more than ever," he said. "I would get drunk every night and go home with someone different every night. [I was] slowly self-destructing. I really didn’t care."

"Back in my drinking days, I tried to commit suicide a couple of times," he continued. "One time in the dead of winter I was so down on myself I laid down in the middle of the street half hoping a car would run over me. No such luck. I had to get up off my ass [and] kept on trying to figure out how to make a living."

Nelson also described the creative struggle of putting yourself in a dark place to write music.

"A lot of guys aren’t happy unless they’re miserable. And I went through that," he recalled. "I thought that was the way it was supposed to be done. I thought we were all supposed to sit down and write how terribly sad and rejected we were. … I think that’s true to a certain extent."

"I still think there’s a danger of getting into it too much where you [can take] yourself right to the bottom with all those negative thoughts. I saw other people miserable writing songs, they would be the cause of all these bad things happening, but then from those bad things would come one hit song after another. It was almost like a person intentionally throwing themselves in the pits of hell and wallowing around in all that muck and mire just so he can come out and say, ‘I’m a songwriter and I wrote a song and I put some soul in there.’"

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Nelson met his second wife, Shirley Collie, while estranged from Matthews.

Together, they recorded a duet titled "Willingly," which Nelson said was an apt description of their attraction.

"The title just about summed up the sexual vibe we felt in the studio," he said.

A voice-over from Matthews recalls, "From the very beginning there was something about [Shirley] that was after Willie. And I could see it. And they got together."

Nelson and Matthews divorced, and he married Collie in 1963. The couple moved to a remote area in Tennessee.

It seemed like he was on track to retire, but soon he was back on the road, leaving Collie to raise the children.

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"I became insanely angry at Willie for being away so often," Collie says in an older interview voice-over (she died in 2010). "I had never had any kids and didn’t know anything about raising kids, and here I was raising three kids, and that’s when things really began to fall apart for us." 

Nelson admitted "absence does not make the heart grow fonder" and said that one day Collie saw a bill from a Houston hospital for the birth of a baby girl, Paula Carlene, born to Mrs. Connie Nelson, actual name Connie Koepke.

"Shirley wanted to know who in the hell was Connie Nelson," Nelson said. "The truth is Connie had been my girlfriend for several years before becoming pregnant."

"She had no idea there was a Connie," Lana added. "She had no idea there was a baby until she got the hospital bill. That’s how she found out about Connie. That’s how I found out about Connie."

Koepke said that at the time "the farthest thing from my mind was getting pregnant and telling my mom and dad."

"Anyway, it happened," she continued. "Honestly, I was the next one, and I don’t mean that in a bad way, but it's just Shirley wasn’t their mother, now she’s gone. I bonded with those kids so much. I loved those kids. They all became my kids, too."

Nelson and Collie divorced in 1971. He and Koepke married that same year and later had a second daughter, Amy Lee Nelson.

According to Paula, for her older half-siblings, Susie, Lana and Billy, her mother was "the new girlfriend, then wife, so it was hard for them."

She added, "But we're all close. And that's Dad's doing. He’s the one that kind of brought us all together as one big tribe."

Shortly before Christmas in 1970, Nelson’s Tennessee home caught fire.

Paula was napping in her crib in a back bedroom, and Billy smelled the smoke, raced to the room and ran outside with her.

"If it hadn’t been for Billy, that could have been it for Paula," Koepke said.

Nelson had been in Nashville when the fire occurred, and his nephew called him, screaming to hurry home.

When he arrived, he ran into the burning home to rescue his treasured and signature guitar, Trigger, and "a bag of primo Colombian pot."

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"I wasn’t about to lose a couple of pounds of good pot," he added.

"Sometimes disruption and even material destruction can help you rethink your priorities. Something about that Ridgetop fire told me it was a time to get a move on," Nelson reflected, noting he wanted to return home to Texas.

There, he began focusing on physical fitness, including beginning karate.

He also realized "tobacco and liquor contained poisons that were injuring me and, increasingly, I saw how pot was mellowing me out."

His sister, Bobby, added, "Willie would never have been the Willie Nelson of today had he stayed with alcohol. Smoking pot has saved him."

Nelson even recalled that he smoked weed with Jimmy Carter’s son while visiting the White House, saying he and the former president got to be "good friends."

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As Nelson explained in the second episode, not only was his family, of course, considered his family but so, too, were members of his band, which helped during an unexpected confrontation with daughter Lana’s ex-husband.

Lana said she "was married to a guy who had some anger management issues, and he took it out on me."

Nelson recalled, "It really pissed me off when he beat her up, so I went over there and slapped him around a little bit, told him not to ever do that again. Then he [came] back, taking shots at the house."

He and his late bandmate, Paul English, went out with guns of their own, "a shotgun and an M1," as English recalled in a voice-over, and shot back at Lana's ex's car.

"I was standing in the door of the barn, he shoots back and one of the bullets hit about two [feet] from the door," Nelson said. "It sounded like World War III breaking out."

"We had the whole family there," Lana recalled. "My mother, who is freaking out, is screaming, 'Oh my God, oh my God, we're going to get killed!'"

Koepke says she grabbed Matthews, Lana’s mother, and told her to "get down, you’re going to get killed." Koepke then added with a laugh, "That's how I met Martha."

Nelson and English shot up Lana's ex's car, but he was able to drive away.

"It was a series of near misses," she said.

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Nelson said after 30 years of smoking, he experienced a collapsed lung.

The incident occurred while he was in Hawaii in 1981 after he had gone for a run on the beach and a swim in the ocean. He explained that the cumulative issues in his lungs along with the pounding water and change in temperature caused his lung to collapse.

The singer was able to get back to the beach and spend 20 to 30 minutes trying to regain enough air to get to his hotel and call paramedics.

The paramedics "stuck a tube through my back, up through my rib cage, into my lungs so it would inflate itself. The next morning, the lung [had] gone done [it] again, so they had to go back in there and do it twice."

While he recovered, he said there was "nothing else to do but write." His next hit was "Little Old Fashioned Karma."

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Nelson got into acting through a friendship with Robert Redford. But it was during the filming of "Stagecoach" with Johnny Cash and Kris Kristofferson, that he met his current wife, Annie D’Angelo.

He was cast as Doc Holliday, and D'Angelo was his hair and makeup artist on the film at the time. She recalled telling him, "Mr. Nelson, I’m the makeup artist. The producer and the director would like to know if you’d be willing to cut your hair for this film."

He asked what she thought, and she answered, "Honestly, I don't see the point. And he said, 'Then let's tell them no.'"

She continued, "Right then we had this little connection. He taught me dominoes on the bus, and we just really connected."

Nelson recalled, "I never had met a woman like her before. She was whip-smart with a keen appreciation for all forms of art. She was pretty and radiated enough energy to light up any room she entered. I fell head over heels in love with Anne Marie D’Angelo, called Annie."

He divorced Koepke in 1988 and married D’Angelo in 1991. The couple had two sons, Lukas and Micah.

Looking back on his relationship, Nelson said, "I’ve always said there’s no such thing as a former wife. Once in your life a wife never leaves. I regret the pain I caused Connie, and Martha and Shirley before her. And I have no excuses."

"I’d be hard-pressed to define love. I know God's love is pure, but worldly love is flawed love, and lots of times confused love. When it came to romance, I had a gift for complicating things, but marrying Annie wasn’t complicated at all. It’s about the smartest thing I ever did."

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In 1990, Willie learned he owed $32 million in income taxes to the IRS.

"It seemed like a lot of money, but it was a challenge," Nelson said.

His tax issues went back to 1976 when he released "Red Headed Stranger," and while the money came in, Nelson’s business manager, Neil Reshen, didn’t pay any taxes and filed extensions to avoid paying any debts down.

Reshen was fired, and as Nelson continued to earn more money, he still owed back taxes. The "Roll Me Up" singer attempted to invest in ventures as write-offs and faced other bad-money management advice.

"I was advised to do bankruptcy, and that wasn’t my plan at all. I never intended and never will do a bankruptcy where the people I owe get screwed out of their money. No."

While the IRS had seized most everything, friends of Nelson’s were able to retrieve his guitar, Trigger, as well as the piano used by Bobbie.

Nelson released "The IRS Tapes: Who’ll Buy My Memories?" with profits going toward paying his debt, which was cleared by 1993. Some of Nelson’s assets were bought back at auction by friends, including farmers he had supported during Farm Aid, and returned to the singer.

In 1991, Nelson lost his eldest son, Billy, to suicide at age 33.

Billy’s siblings recalled their brother’s struggles, which they said worsened over time.

"We were 17 months apart," Susie said. "We did everything together, but he had a lot of issues. And then, of course, later on in years, they became more and more."

According to Lana, Billy had "depression," adding, "I think if there’s anything that goes in our family, it’s depression. He didn’t want to be depressed, he didn’t want to be that guy. He tried really hard, he did."

Paula added that Nelson’s fame may have been an issue.

"He really was a wonderful guy, but it’s hard to be in Texas when your dad’s Willie Nelson. You can’t get away from it," she said.

She continued, "When my brother, Billy, passed, it was terribly hard on him, on all of us. It was really hard for him because that was his first son."

Nelson doesn’t speak directly about losing his son, but his sister, Bobbie, said, "It wasn’t that we had long talks about our grief, that’s not Willie’s way. We didn’t have to talk about it. We knew."

Nelson’s younger son, Lukas, shared his admiration for his father.

"Dad has been homeless, he’s had his house burnt down, he’s been through four marriages, he’s been up and down, he’s been broke, he’s fought the IRS, he’s lost a child ... that’s what makes him inspiring to me: His resilience in the face of adversity," he said.