My mother, Evelyn, was an actress and singer, and my father, Jack, was an actor. My earliest recollection of my father is being taken to see him in a matinee. I have a vivid memory of me, in the back of the taxi afterwards, saying, "Dad, that's what I want to do." They looked at me and said, "Yes, you can do that, but not until you graduate from school." I was three.
My parents split up soon after. My mother gave up a good part of her career to look after me. I lived with my grandparents when she was on tour. My mother had five siblings and she was the only one to survive and I was the only grandchild, so they really loved me. My grandmother led the senior church choir and I was the lead vocalist for the juniors. My grandparents gave me a really strong, positive, loving foundation.
When I was 11, I moved to Los Angeles to live with my father and stepmother and my half brothers. I became really close to my stepmother, and I am still very close to my brothers. My stepmother is the actress Shirley Jones, who was in The Partridge Family alongside me, so we worked together for years.
When I was 18, two weeks after I graduated from school, I left LA and went back to New York. That voice in the back of the cab had never left me. My first professional job, nine months later, was in the same theatre on Broadway where I saw my father perform that day when I was three.
My dad was a boot-camp sergeant: we work until our fingers are bleeding – that's how we rehearse – until we get it right, even if that takes 16, 18 hours a day. I thank him every day for that. But he didn't take it at all well when I became this very famous guy. His ego found it really difficult. For the first years of The Partridge Family he was Mr Shirley Jones, and then he was David Cassidy's dad. They divorced, and he resented the hell out of me. All I wanted was for him to put his arm round me and say he was proud of me. I never got that.
As a father, I do everything my dad didn't do. My son Beau's birth changed my life. I've gone to every baseball and basketball game, every performance. And I'm still with Sue [Beau's mother, the singer-songwriter Sue Shifrin] after 25 years. I did swing and miss a couple of times [two previous marriages] but 25 years is big time in my business!
Beau has just turned 21 and left college to pursue his dream. He's got a band called the Fates. I am very, very proud of him. My wife and I look at each other and say, forget songs, shows, theatre – when you're responsible for a human being who is really good – caring, loving, sensitive – there's a lot to be proud of. I hope he makes it.
My mother has just had her 89th birthday but has disappeared into severe dementia. She can no longer speak or walk. It is terribly painful to watch. For the last eight years she's lived in 24-hour nursing care. I vetted four facilities and I think I found a good one. Celebrity has a few perks – a good table at restaurants and the care home knowing that if they screw up it will get a lot of publicity.
I've been speaking on behalf of the Alzheimer's Foundation of America. I've decided to dedicate a lot of my energy to try to raise awareness, educate and raise money for dementia care. Caregivers are my heroes now and I want to do my part to help.
• David Cassidy headlines the Once In A Lifetime UK tour with Leo Sayer, Hot Chocolate and Smokie, nationwide from 9 November. Tickets: 0844 847 1726, ticketmaster.co.uk.
