Sean PennSean PennSean Penn has revealed what went wrong in his marriage with Madonna - 16 years after their doomed relationship ended in divorce.

"Had we stayed together," he said, "We'd have driven each other mad."

The couple, who met on the set of Madge's Material Girl video, had one of the most turbulent relationships in Hollywood history. 

But up until now Madonna had been the only one to offer insight into why they divorced - citing Sean's desire to be a dad as the reason. 

The fiercely private actor revealed the relationship thrust him unwillingly into the public eye, making him a "nightmare" to live with.

Guy And Madge Team Up AgainMadonna now, with Guy Ritchie"I just wanted to make my films and hide, so there was never going to be an easy solution.

"I don't really know who could have lived with me at the time," he told Now magazine. 

Sean gallantly had only good words for the mega pop star, praising her as "very real, very sensitive."

Luckily, both Sean and Madonna have gone on to enjoy successful marriages elsewhere.

Madonna is now happily settled with director Guy Richie and her two children, and Sean will celebrate his ninth wedding anniversary with actress Robin Wright this month.