Earlier this year, Glen Campbell‘s widow, Kim, honored the country star by creating The Glen Campbell Museum — and now she’s announced another way to celebrate her late husband’s memory.

On Tuesday, Glen’s birthday, Kim revealed that she’s written a book about their decades-long relationship, Gentle On My Mind: In Sickness and in Health with Glen Campbell, which will be published by Thomas Nelson on June 23.

“As I celebrate Glen’s birthday today, my mind is flooded with memories of our 35 years together,” Kim told PEOPLE in an exclusive statement. “To the world, Glen was a star of TV and film a legendary singer and guitarist who sold over 50 million records, earned six Grammys, and brought country music to the mainstream with hits like ‘Rhinestone Cowboy,’ ‘By The Time I Get to Phoenix,’ and ‘Wichita Lineman.’ To me, Glen was my husband, my best friend, and the father of our three children.

“He remained humble even though he was one of the best looking and most talented men on the planet, often jesting, ‘I don’t think I’m half as good as I really am,'” she continues. “Armed with a sense of humor and strengthened by our faith in God, we weathered the storms of Glen’s battles with alcoholism, drug addiction, and ultimately Alzheimer’s. To celebrate our remarkable life together I am sharing our incredible love story in my new book, Gentle On My Mind: In sickness and in health with Glen Campbell.”

Glen — who would go on to win numerous awards, first as part of The Wrecking Crew in the early ’60s, and later as a solo performer — married Kim, a dancer at Radio City Music Hall who was 22 years his junior, in 1982. Together they raised three children, Cal, Shannon, and Ashley. (Glen also had five children from three previous marriages.) After decades together, the music legend died of Alzheimer’s disease in August 2017 at the age of 81.

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But this is only a short summary of what Kim describes as their “incredible” and tumultuous life together.

Gentle On My Mind traces their epic highs together, from hitting the top of the music charts to interacting with fellow stars like Mick Fleetwood, Jane Seymour and Waylon Jennings. The book also reveals the hardships they faced. Kim delves into Glen’s addiction to drugs and alcohol and their harrowing journey after he was diagnosed with Alzheimer’s in 2010 at the age of 74.

The “Rhinestone Cowboy” singer went on a farewell tour in 2012, which eventually encompassed 137 dates. During the tour, Glen permitted a film crew to document his battle with the disease. The resulting 2014 documentary, I’ll Be Me, was nominated for an Oscar for best original song for “I’m Not Going to Miss You.”

“The goodbye tour was one of the biggest blessings for Glen that anyone could have imagined,” Kim told PEOPLE in November 2017. “The doctors emphasized to us that music was stimulating for the brain and it would be healthy for him. It was Glen’s choice to do the film. He loved the camera — after all, he did a TV show for years. That was part of who he was. He said it was the most important thing that he was doing at the time. He knew he was trying to show the world what living with Alzheimer’s was like because he wanted to help find a cure.”

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But, after the tour was over, Glen struggled greatly.

“There were times he’d wake up and look at me and go ‘Are we married?’ He quit calling me by my name a long time ago,” Kim told PEOPLE about her husband’s frightening decline. “And then, he grew combative. He gave me a black eye. I’m younger than him and faster than him so I avoided a lot. You don’t take it personally. It’s part of the disease. They lose their ability to communicate verbally so if you are trying to do something they don’t like, they instinctively lash out.”

In 2015, Glen moved into long-term care, eventually settling at Abe’s Garden, a memory care facility in Nashville. While Kim received some criticism for the decision, she explained that it was the best move for Glen’s health. She explained how hard the battle against Alzheimer’s was for them as a couple and their children.

RELATED: Two Years After Glen Campbell’s Death, His Widow Says It’s Still ‘Heart-Wrenching’

After the star’s death, Kim was better able to remember the joyous times they shared.

“There was a time when all I could remember was the sickness,” Kim told PEOPLE in 2017 about the impact of the disease. “But now that he’s passed, the good memories are starting to flood back in.”

Kim hopes that her book will not only help educate people about the challenges of Alzheimer’s — a goal she shared with Glen — but give a complete portrait of the husband and father behind the epic hits.

“He was 22 years older than me but age didn’t matter between us — he was so young at heart and excited about ordinary things,” Kim said in 2017. “Life was just beautiful.”

Source: People.com (https://people.com/country/glen-campbell-widow-kim-writes-book-incredible-love-story/)