Despite unbelievable fame in the '70s, the decades that followed were marked with turmoil for David Cassidy, now 66 and battling dementia

By the time David Cassidy turned 21, he had made his first million.

The actor had won hearts worldwide as the hunky, young star of The Partridge Family in the 1970s. Despite unbelievable fame, the decades that followed were marked with turmoil for Cassidy, now 66.

Cassidy revealed exclusively to PEOPLE on Monday that he is battling dementia and that he is stepping back from touring as a musician to “enjoy life” and “love.”

At the peak of his early career, Cassidy played some 350 concerts in 17 countries while releasing 10 Partridge albums, eight solo albums and 17 singles, PEOPLE reported in 1983. Cassidy would fight off aggressive fans – things at one point got so out of control that he had to be smuggled into his own concerts.

Cassidy in 1970
| Credit: Michael Ochs Archives/Getty
Cassidy in 1972
| Credit: Photoshot/Getty

“I was a kid, not a man,” he told PEOPLE in 1983 of having to semi-retire, exhausted, at only 24. A friend, Samuel Hyman, noted at the time, “If David hadn’t done all those years of seven-day weeks—acting, touring, recording — he might not have been driven to the edge. I think he had to stop for his mental well-being.”

Cassidy was more than happy to leave Keith Partridge behind. He told PEOPLE in 1973, “There’s a lot more to me than the public has seen and I’m going to make sure they see it. Now I’m free. It’s as if a tremendous weight has been lifted off my shoulders. I feel I’ve finished on top.”

The Partridge Family
| Credit: ABC via Getty

Cassidy disappeared, traveling alone to visit friends. While he was gone, his estranged father Jack Cassidy died in 1976. Said Cassidy of the loss: “I just wish I could have talked to him before he left. I didn’t have a chance to say ‘I love you.’ ”

The next year, Cassidy wed actress Kay Lenz. The marriage fell apart, however, with Cassidy telling PEOPLE amid their separation in 1983 that “Kay had her own life, and I had different needs.”

Cassidy and wife Kay Lenz
| Credit: Waring Abbott/Getty

Soon, he was engaged to horse breeder Meryl Tanz, who told PEOPLE that same year of her fiancé: “A lot of people in rock have died or been impaired by drugs or whatever. He is sane, normal and clean-living.” They wed the next year, but the marriage was also short-lived.

By 1986, Cassidy was a first-time dad, welcoming daughter Katie Cassidy with on-again-off-again girlfriend Sherry Williams. With another television series under his belt (the short-lived David Cassidy: Man Undercover), a Broadway stint and a new studio album, Romance, Cassidy’s return to prominence was underway.

Cassidy with daughter Katie
| Credit: Jean Baptiste Lacroix/WireImage

Another marriage, to songwriting partner Sue Shifrin-Cassidy would follow; as would the birth of son Beau in 1991. Soon Cassidy was drawing crowds again, this time as he costarred with brother Shaun Cassidy in Broadway musical Blood Brothers.

Cassidy with wife Sue Shifrin-Cassidy
| Credit: Ron Galella/WireImage
Cassidy with wife Sue and son Beau
| Credit: Jeff Kravitz/FilmMagic

For Cassidy, the show and marriage marked a re-emergence from “a couple of really dark, dark years,” he told PEOPLE in 1993. He added, “I’ve made a tremendous metamorphosis.”

David Cassidy Ups and Downs

After a decade marked by success with Las Vegas productions, and a brief return to television on the late 2000s with series Ruby & the Rockits, Cassidy was again plagued with personal issues.

In 2010, Cassidy was arrested for a DUI in Florida. In August 2013 and January 2014, he was charged with the same offense.

After the 2014 incident, Cassidy’s publicist told Entertainment Tonight, “David just completed a stint in rehab and was doing very well in sobriety. He was in Los Angeles to attend depositions by Sony Pictures Television, respondents in a lawsuit filed by Cassidy in 2011 over what he claims are monies long due him from Partridge Family merchandise, home video, etc. After attending his and his manager’s depositions, it appears as if the pressure led to a brief relapse.”

“He was on his way to the airport to return to his home in Florida and to transitional rehabilitation. He plans now to return to rehab in an undisclosed facility,” the statement said.

The next month, Shifrin-Cassidy filed for divorce after 23 years of marriage. By 2015, Cassidy had filed for bankruptcy and was charged with a hit and run in October of that year.

Cassidy in 2012
| Credit: Steve Thorne/Redferns via Getty

On. Feb. 20, 2017, Cassidy announced that he would retire after performing a few, final concerts – ending a nearly 50-year career. In a Facebook message to his fans, Cassidy wrote on Feb. 7, “I will always be eternally grateful for the love and support you’ve shown me.”