When my autobiography, Who Does She Think She Is?, came out [in 2000] I was touring and doing a million different things, and had [ghost writer] Matthew Wright on board. My dad had been selling stories about me to the tabloids and that book was a way to get some control back.

There has been criticism of me being a celebrity and writing a novel. Everyone’s entitled to their opinion but I wrote The Mistress because I was passionate about it. I wanted to prove to myself that I could do it. The most important thing is the public – the people I want to enjoy the book.

There were embarrassing moments while writing the novel. I was sitting with my mum [author Jenny Tomlin] in the Dordogne, where she lives, and we were both dosed up on coffee. I was reading a sexual scene out loud because I was on deadline and my mum suddenly burst out laughing. She said: “I can’t believe you’re saying this so mechanically. You’re my daughter and I love you, but this is quite embarrassing for me.”

I’ve been asked to be a mistress on a couple of occasions – there are some naughty married men out there. But it’s an idea I could never entertain, because from a young age I’ve been aware fame is a responsibility. As the “nation’s sweetheart” – the media’s description, not mine – the two things wouldn’t go hand in hand. I’ve been fortunate that the people I’ve fallen in love with haven’t been married. It’s easy to condemn or judge people’s love lives, but no-one knows what goes on between two people except them.

I think I’ve managed to shed my “unlucky in love” tag. In this country, more than anywhere, the tabloids are lazy with their labels and don’t want to move with the times. I’ve actually found myself lucky in love a couple of times and I wouldn’t change those experiences for the world. They helped me know what I wanted for the next time – and what I definitely didn’t want. As a result, I’m making wiser choices.

My mistakes have been well publicised but they’re mistakes just like everyone else’s – and they hurt me just as much as they would hurt anyone.

Much is made of the fact my boyfriend [musician Jack McManus] is younger than me [McCutcheon is 33; McManus is 25]. We still live in a world with certain standards that are out of date. So it’s okay for an older man to go out with a younger woman, but if a woman goes out with a younger man she’s portrayed as a sexual predator.

The thing I’m most proud of is my endurance. I’ve always managed to see the funny side. When things are at their darkest, somewhere, somehow, I can pull a giggle out and get everyone to laugh with me.

Everyone seems to be fascinated with my weight. The biggest misconception is that I’m chunky. It doesn’t bother me, though, because I know I’m wearing the same outfits I wore when I was 21. I’m always between a size 10 and a 12.

Loyalty and discretion are what I crave most in my friendships. I don’t like gossip. If a friend was to tell someone something I had asked them not to, that would infuriate me. It’s something I have to worry about with work and I don’t want to have to worry about it in my personal life.

I’ve never wished things in my life were different. I don’t regret anything – I just wish I could have learned certain lessons a little quicker.

The Mistress is published by Pan, priced £6.99.