Ayda Field says "every time" she turns on the TV she "spots" someone Robbie Williams has bedded.
The 37-year-old actress revealed the couple have made a "running joke" out of spotting his sexual conquests on the telly.
She said: "It's my running joke with Rob that every time we turn on the television, he's slept with someone. I love the game. It doesn't matter if it's a prize drama or a TV show, there'll be somebody he's slept with".
She added: "It even happened at a 'Mummy and me' class in Los Angeles once. All of a sudden, Rob drops and rolls into the foam pit, and is like 'Pssst, babe, come here, I slept with that mum and I can't remember her name.'"
Robbie previously dated Hollywood starlet Nicole Kidman, singer Nicole Appleton and two members of the Spice Girls including Mel C and Geri Halliwell, but Ayda says any "blonde" famous woman in the 90s could have had a fling with the star.
She said: "He's been totally open about it all with me, and basically if she was blonde, in the 90s and famous, it happened. I'm so not bothered though. What's gone is gone - it happened before me. It would only bother me if it was happening during me."
Meanwhile, the happily married couple have a strong bond because they share similar attributes and Ayda admitted they've both benefited from lots of therapy.
She told The Mirror newspaper: "We are both emotional, very sensitive and people pleasers. Behind closed doors, Rob is a real teddy bear, a big softie.
"It's probably because we are both so over-therapied that we are always talking things through. We never go to bed on a row. Therapy is so personal but it can be a really amazing tool so long as you are not forced into it."