Gwyneth Paltrow was heartbroken after her best friend died in a car crash.

The 'Iron Man 3' actress - who lost her father Bruce to cancer in 2002 and recently revealed she miscarried during her third pregnancy a few years ago - claims she has suffered a lot more than people realise but it has made her determined to make the most out of her life.

The 40-year-old blonde beauty told Glamour magazine: ''I've had a great deal of suffering in my life. I've lost people - my first cousin, my best friend in a car accident. I've had a lot of things happen to me that I don't talk about in the press.

''I've had a lot of really heart-breaking, difficult things. But all of those things have strengthened my resolve to make the best of my life.''

The Oscar-winning actress, who has a seven-year-old son, Moses, and an eight-year-old daughter, Apple, with her husband Chris Martin, also revealed that the couple have managed to stay married for 12 years because neither of them ever wanted to file for divorce at the same time.

She said: ''It's hard being married. You go through great times, you go through terrible times. We're the same as any couple.

''I asked my dad once, 'How did you and Mum stay married for 33 years?' And he said, 'Well, we never wanted to get divorced at the same time'. And I think that's what happens.

''When two people throw in the towel at the same time, then you break up, but if one person's saying, 'come on, we can do this', you carry on.''

But she insisted that she and the Coldplay rocker have a great relationship and she believes he is a ''genius''.

She said: ''We laugh, we're good friends, we like to do the same stuff.

''I'm a very grounded, homey person and Chris is a very mad scientist, genius songwriter.

''So I never say 'Where are you? You should be home by now'. I never place demands on him because I think he's a really talented man and he's putting something good into the world.''