The 41-year-old star, who started dating Kournikova, 35, back in 2001, has always been content and secure about his relationship, with marriage not making a difference, reported E! online.
"I don't believe you need a piece of paper to show you love someone," Iglesias said.
But when asked if he had any plans to wed, he said, "Who knows what the future holds... Or the past...Haha."
Recently Kournikova was spotted sporting a large diamond and gold band on the ring finger.