Allen has been away for a week on a trail ride. He has been in the outback, country so remote that cell phones don't work. Out of touch.

I'm used to being alone. Often I'm in Marin and he's at the ranch. Being apart has become the way we live. Being away from each other for two, three, maybe five days has become the norm. But we're always in touch.

A call in the morning to start the day and a call in the evening to say good night. We usually don't talk very long. I'm not one for extended phone conversations. Get your business done and move on. But it's enough to touch base, to know each other is all right, to say a quick, 'I love you.'

For almost eight days now we haven't spoken. A huge silence, an enormous absence. For Allen I suspect the time has raced by. Everything new. New terrain, an unfamiliar horse, a new group of friends, trusting new mentors, steep learning curves as well as the beauty of the high country.

For me I've finished another screenplay, got word that my last script has placed in an important competition, rendezvoused with friends, taken long walks with the dogs. Sometimes only with Bill, the young Border Collie. The longer hauls are too much for our old girl, Sally. But always I've been thinking of Allen. Missing him.

Living apart is not unusual.

Recent research estimates that in England there are now as many as two million couples who, despite being in a committed relationship, live separately. They are known as LAT's or Living Apart Together.

Some have made a conscious decision to keep their domestic lives apart. Other have arrived at this point sometimes because a previous cohabiting relationship has broken down, or they do not want to impose a new partner on children from a previous relationship. Some are apart due to competing work commitments or family responsibilities.

In Sweden, which has witnessed similar trends in divorce, marriage and people living alone as Britain, the number of LATs has risen from just six per cent in 1993 to more than 14 per cent at the last count five years ago.

Word has it that Woody Allen and Mia Farrow lived in different homes on either side of Central Park, New York. The actress Helena Bonham Carter and the director Tim Burton have one son but two houses, next door to one another in Hampstead, North London. The Booker prizewinner Arundhati Roy lives in a rooftop Dehli flat while her film-maker husband Pradip Krishen lives in a separate house in the city.

I prefer living together...most of the time. Sure, there are those moments when Allen would like to give me the boot, and times when I would be happy to return the favor. But when the end of the day rolls around there's great comfort in comparing notes, indulging in a good old fashioned heated political discussion or just sharing some of the reflections that have popped up. There's a need to check in.

A need to be in touch.