Pop star Madonna and her estranged husband Guy Ritchie didn't have sex for 18 months as their marriage crumbled, it has been reported.

The couple - who announced last week they were separating, ending months of rumours - reportedly didn't get close beneath the sheets because the Hung Up singer was too tired for love due to her gruelling daily four-hour workouts.

A friend close to the pair said: "Guy got more and more frustrated as she spent nearly half the day exercising. When she did eventually get home she'd be too tired to make love.

Gwen helps Madonna Video