In a BBC series about the wisdom of age, the designer Mary Quant offers some sage advice. "The key to a happy marriage," she says, "is separate bedrooms, separate cars." Some time earlier, the comedian Rodney Dangerfield went further. "We sleep in separate rooms, we have dinner apart, we take separate vacations," he joked. "We're doing everything we can to keep our marriage together."
Since Adam and Eve had their first row about whose turn it was to tidy up Eden, couples have realised the benefits of spending a little time apart. But for Mary Austen, who lives in Barcelona with her two daughters, all this still sounds dangerously claustrophobic. "My husband and I have never lived together," she says. In fact, Pierre lives in Paris and visits her and their children for long weekends. During the week, she watches Desperate Housewives videos back-to-back and has wild nights out with her friends. She says it is the best relationship she has ever had.
Couples like Mary and Pierre are a growing phenomenon, according to the Office for National Statistics (ONS). In its new winter report it identifies a social trend that is growing so rapidly it has been given its own acronym. Living Apart Together relationships (LATs) happen when two people are in a committed relationship but live apart. The ONS estimates that 2 million people are LAT-ing: three in 20 people aged 16-59 - about the same as those cohabiting.
The ONS dryly describes true LATs as "the existence of a relationship, which is understood to include a sexual relationship, between partners who each have their own separate address". It is not quite how Catherine and Chris, a couple in their late twenties, would describe themselves, but a LAT is exactly what they are. "We've been together for four years," says Chris, "and we love each other very much. But I don't think I could bear to live with her. She's lovely, but she's the messiest person in the world."
Early on in their relationship, Catherine and Chris bought flats separately in south London, and the Living Together conversation was not one they ever had. And now they are too happy as they are. "I began to think I would never own my own place," says Catherine. "Now that I do, I never want to give it up. It's lovely to wake up on a Sunday morning with somebody. But sometimes, it's even lovelier to wake up on your own."
Couples like Chris and Catherine form one distinct category among the four LAT groups identified by social scientists. One is young couples who, like them, are determined to keep their own flats. Another is the widowed, who want to ensure that their children inherit their property. A third group covers professionals who work in different cities - or even countries, like Mary Austen and her husband, Pierre. "I'm sure it works so well because I have the chance to miss him," she says. "When you live together, things become more common and comfortable. Now when he arrives I feel like dressing up so he can take me out for dinner. It feels like we're going out on a date."
A fourth category includes people such as Rebecca Ashworth, 54, and her partner John Michaels, 43. These are people who have one failed cohabiting relationship under their belts, and are determined to do things differently second time around. Rebecca is divorced. "There is obviously that fear of becoming too dependent on somebody," she says, "but mostly we have always believed that our relationship is so good because we don't live together. When you're with somebody during the week you have the worse end of the relationship: all the domestic crap. But we've never had the shopping and the washing: we've just had the quality time."
If a fifth category were to be added, wealthy celebrities might be it. The singer Natalie Imbruglia works from London while her husband of two years, Daniel Johns, frontman for the Australian grunge rock group Silverchair, stays down under. "I would never put any pressure on him to move," she has said. "He's got so many more songs written in the weeks he's been away from me." Diane Kruger, the star of Troy, and her actor husband Guillaume Canet live separately, in Paris, while Toyah Willcox and her husband of 12 years, guitarist Robert Fripp, feel lucky if they get one month a year together. "I like the freedom," she says, "We're never bored with each other, just always thrilled at the thought of meeting up again and leaping into each other's arms."
Helena Bonham Carter feels the same. She and Tim Burton have been together for five years and, despite having a two-year-old son, Billy Ray, feel that maintaining separate households enhances their relationship. They live next door to each other in London. "I've always needed my own space, and Tim definitely needs his because he works from home," she says. "He paces everywhere and he couldn't always be pacing in my space because it would drive me absolutely potty. We have the ideal setup. We can visit each other when we want and have our privacy, too."
As long as a couple is in agreement about these arrangements, the LAT relationship can work very well, says Paula Hall, a sex therapist and couples counsellor with Relate. "Lots of people live together because financial resources or time resources are short," she says. "One house is cheaper than two, and it is as quick to cook and clean for two as for one. The more money you have, the less that matters. People are now realising that time apart and independence are very healthy for a relationship."
John Haskey, a statistician and demographer at Oxford University and the author of the study, is more cautious. "It is not about a lack of commitment or an increase in individualisation," he believes. "It is very much that caution is holding people back from situations they saw as risky."
In part it may be the "once bitten, twice shy" feeling of people who have had their fingers burnt, and others may wag a finger at commitment-phobic men. But talking to LAT couples, I start to get the sneaking feeling that it is the choices of women that are driving this trend and making the decisions.
Phillip Hodson, a fellow of the British Association of Counselling and Psychotherapy, agrees. "Within a generation, we have a lot of women in Britain now who are householders and have their own money and independence, and they are unwilling to give that up. Particularly in English culture, where housing is very symbolic. It's your nest; it's your castle."
That is certainly the case for people like Mary, who says that she has never had it better. "We have lots of holidays apart, too," she says. "All my friends wish their relationships were the same." Chris agrees. "Maybe we're selfish," he ponders. "But as long as we're both happy, we're not going to change."
After seven years of LAT, meanwhile, Rebecca and John have just, tentatively, moved in together. "I have my own room," she says fiercely. "And I've kept my old flat. And if we decide it doesn't work, I know our relationship is so strong that we can move out again and we won't split up."
LAT isn't for everyone. "Intimacy is about more than proximity," says Paula Hall. "But there are some people for whom waking up together is a very important part of a relationship. Some couples set up businesses together because being apart from nine to five is too long. We all have different ideas of what closeness and intimacy means. They key is to find a partner who has the same ideas as you."
Living Apart: 'Our two sets of children come first'
Karen Barham and Richard Lucas, both 43, have been together for three years. Richard has a daughter, 12, and a son, seven, and Karen a son, five, from previous relationships. They live eight miles apart in villages near Guildford, Surrey.
RICHARD: After about a year of being together we felt a pressure to make a decision about where we we're going. We sat down one night and were totally honest with each other - well, almost brutal really - on the pros and cons of moving in together. I was probably more inclined than Karen to think it would work. But the decision we reached was to live apart. I respect what Karen had to say because she's spent 20 years as a divorce lawyer. We both felt living together would erode our relationship. Our children were so young. I think it can be difficult learning to deal with other children as your own. I sensed the resentment from Karen's son, who was two at the time, and understood that he wasn't enjoying having to share his mum with me. I also wasn't sure about moving into the house Karen had shared with her ex-husband.
I suppose it's disappointing that we've logically reached this conclusion, but we see each other almost daily and I see our relationship as being long term.
KAREN: As a relationship evolves, there is an expected route of evolution, normally cemented by marriage or cohabitation. In our case, rather than go headlong into something we might have wanted for ourselves, we saw the need to shape the relationship around the needs of two sets of children, rather than expect the children to make major changes.I suppose it was very much the head leading the heart.
We've both come from failed relationships involving children. My work has made me alive to the realities of life. Statistics show that second marriages fail at an even higher rate than first marriages. Neither of us wants another failed situation.
There are disadvantages. It makes it even harder to find time to see each other. But there again I don't have to do his washing! But this arrangement doesn't mean I am any less committed to Richard. And when we can set aside time for each other, it feels more like a date. I'm sure when the children are older we will simply know when it's the right time to move in together.
Karen Barham is the chair of Surrey Resolution - an association of 5,000 lawyers committed to the non-adversarial resolution of family disputes. Interview by Neville AckerleyReuse content