Afailed marriage is an emotionally and financially expensive social scourge, which is why it has received so much research funding over the decades. But all the studies seem to have had no discernable effect on rocketing divorce rates, especially in countries where women have achieved a significant degree of equality with men. It is not that marriage has become any less popular, although many theorists believe it is outdated. Almost all men and women still hope to marry (or remarry) and for their marriage to last. They see it as a source of happiness. And there, perhaps, is the problem. Marriage used to satisfy more defining material and social needs. So, the happiness it brought was just one part of the package. Also, because it used to have more weighty and gratifying social clout, there were lots of peripheral happiness to be had - not all marital delights necessarily came directly from the husband-wife relationship. Even today, although not bliss-inducing, the contentment side-effect brought by the long-term social status of marriage is significant. However, nowadays it is more possible and socially acceptable to live and even have a family independently. Consequently, marriage more often hinges on the happiness quotient of the relationship. For a woman, having such a choice is a privilege. In global terms, most women, such as those in developing countries, still depend on marriage for survival. It can be agonising for today's woman to think she is throwing away the freedom earned for her by her mother and grandmother on a less than thrilling alliance. The trouble is that one of the great disillusionments that psychological research has provided us with - and repeatedly confirmed - is that, although people have strong positive and negative reactions to life events such as marriage, their level of happiness eventually returns to their personal norm; what some psychologists call 'hedonic levelling'. So, for example, widows and widowers are less satisfied with life after the death of their spouse than before they got married. But even they adapt and eventually attain satisfaction levels close to before. The happiness levels of people who are already most satisfied with life when single are the least affected by marriage, either positively or negatively. However, despite the hedonic levelling principle, an entire industry and an increasing number of researchers are no longer trying to find what they used to look for - what was wrong with bad marriages. Instead, they are examining exactly what goes right, and piecing together what could be the basic ingredients of a happy, successful, or at least long-lasting, marriage, which by today's less-than-idealistic standards is anything more than nine years. What do these satisfied spouses have in common that unhappy ones do not? Nothing could be simpler. Unless you live in a vacuum, you will know the magic formula: Happy spouses remove themselves psychologically from their previous life orientation and honestly commit to a new way of life. They respect their spouse's autonomy, yet offer unflinching support where required. They make time for sex, even at taxing times, such as when a baby arrives or when work pressures mount. And, when times get tough, they continue to bring romance and humour to the relationship. A bad marriage is far worse for a woman's mental and physical health than for a man's. This is probably because of differences in how men and women process emotions. Women are more porous to their spouse's state of mind - they detect and take on the physiological arousal that goes along with negative moods. Men are just as good as women at figuring out what their spouse is feeling. But they tend to stonewall when a particular mood does not suit them. Women tend to have the instinct to engage. This leads wives to feel frustrated and even more stressed. In poor marriages, these continual heightened stress levels have physiological effects that result in poorer health. Overall, then, marriage is still a better deal for men than women. In itself, however, it brings lasting bliss to neither. That is something imported into the marriage by each individual spouse. In the end, it seems, a happy marriage is simply an alliance of two happy people. Jean Nicol is a Hong Kong-based psychologist and writer everydaypsychologist@yahoo.com