In his new song, “A Better Place,” Glen Campbell sings, “I need the ones I love Lord/More and more each day.”

The lyric is more personal than the world knows: In an exclusive interview with PEOPLE, Campbell, 75, and his wife, Kim, reveal that the singer has Alzheimer’s disease.

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The couple have decided to go public with Glen s diagnosis because he’s hoping to say farewell with a final slate of live performances this fall – and they want his fans to be aware of the musician’s condition.

“Glen is still an awesome guitar player and singer,” says Kim. “But if he flubs a lyric or gets confused on stage, I wouldn t want people to think, ‘What’s the matter with him? Is he drunk?’ ”

The Grammy-winner, whose “Rhinestone Cowboy” topped the charts in 1975, had been suffering from short-term memory loss for years, but the Alzheimer’s diagnosis only came six months ago.

“I still love making music,” says Campbell. “And I still love performing for my fans. I’d like to thank them for sticking with me through thick and thin.”