The key to David and Victoria Beckham's lasting marriage is the fact they are best friends.
The couple, who have children Brooklyn, 16, Romeo, 12, Cruz, 10, and Harper, three, together, celebrated their 16th wedding anniversary last week.
"They're best friends. They've become so close over the years that neither one can imagine living their life without the other, and I think it's changed them both for the better," a source told Look magazine, reports femalefirst.co.uk.
Another source added: "I think they've both realised they can only trust, rely and count on each other. And that's their biggest secret really - they can still make each other laugh after years of being together."