Gene Wilder's widow Karen Boyer is opening up about the final years she spent with her husband.

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In an essay, Boyer shared her experience watching Wilder's battle with Alzheimer's until his death in 2016. The couple were happily married for 20 years after the death of Wilder's first wife, Gilda Radner, and traveled the world together until she started to notice a change in her husband.

"The first signs of trouble were small. Always the kindest, most tender man (if a fly landed on him, he waited for the fly to leave), suddenly I saw Gene lashing out at our grandson," she wrote for ABC News. "His perception of objects and their distance from him became so faulty that on a bike ride together, he thought we were going to crash into some trees many feet away from us. Once, at a party with friends, when the subject of 'Young Frankenstein' came up, he couldn't think of the name of the movie and had to act it out instead."

The late actor struggled with the disease for six years before his death. His widow wrote that even simple day-to-day tasks were difficult for him, and she did her best to protect him from some of it.

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“I watched his disintegration each moment of each day for six years. One day, I saw him struggle with the ties on his drawstring pants. That night, I took the drawstrings out. Then his wrist was bleeding from the failed effort of trying to take off his watch. I put his watch away.” she wrote.

She also recalled the final moments of her husband’s life in the emotional essay, writing, “Gene died fifteen months ago. I was in the bed next to him when he took his last breaths. By that point, it had been days since he’d spoken. But on that last night, he looked me straight in the eye and said, three times over, ‘I trust you.'”

Boyer applauded The Gates Foundation's impressive $100 million donation aimed to help end the disease and said she was grateful to have the opportunity to use one of Wilder's most beloved characters, Willy Wonka, to launch the "Pure Imagination Project," which encourages others to help do their part in fighting the disease.

"It is a strange, sad irony that so often, in the territory of a disease that robs an individual of memory, caregivers are often the forgotten. Without them, those with Alzheimer's could not get through the day, or die — as my husband did — with dignity, surrounded by love," she concluded.