"God, the best maker of all marriages," intones Shakespeare's King Henry V in amorous pursuit of his Kate. A marriage made in heaven. Yes, love gives heavenly transport. Does that imply a perfect union? Of course, not. Truth be told, marriage is sometimes exasperating, confining -- and always sacramental.

It was a goal from our early days to find the right one to marry for life. However, it appears marriage is rather out-of-date, like land lines and library books. And, today it certainly is not about sex. At one time many marriages were shot-gun affairs. That was then. This is now. Readily available sex and birth control have taken away the shot gun and even the need to marry.

A seven-year-old we know was reminded by her mother to start saving her money for college. "I'm not going to college," she replied. "I'm going to be a nun. I don't want to get married and have a husband to boss me around." Is this th new face of feminism?

Surely there are women today who share the little girl's view. They are probably amused by these adages about marriage.

Marriage is neither heaven nor hell. It is simply purgatory.

Marry'd in haste, we oft repent at leisure.

For two people in marriage to live together day after day is one miracle the Vatican has overlooked.

Marriage is three parts love and seven parts forgiveness of sins.

Successful marriage requires falling in love many times, mainly with the same person.

Current research, that sacrosanct arbiter of all weighty questions, suggests a rough climb for modern marriage. The major finding -- no surprise here -- is the decline in marriage and the rise of other domestic configurations. In 1960 (the bright ages if you consider today the dark times), 68 percent of all twenty-somethings were married; in 2008 just 26 percent were married. Generations differ in their attitudes toward cohabitation, remaining single and other new family arrangements, such as same sex unions. No surprise, the younger ones are less concerned about same-sex unions and sex before marriage.

The Pew Center for Research recently asked respondents if marriage is becoming obsolete. Nearly four-in-ten say that it is. As we know, cohabitation and sharing the upkeep is replacing the exchange of wedding bands. Most likely to agree that marriage is outmoded include those who are part of the phenomenon (62 percent of the parents of cohabiters). Whereas those most troubled by these arrangements (42 percent) are self-described conservatives. Still a large majority of respondents say the trend toward single women having children is bad for society. Additionally, 61 percent feel a child needs both a mother and a father. While attitudes toward homosexual couples raising children have softened, still 45 percent think it's bad for society. Nevertheless, few in the survey say alternative family trends are good for society.

What is causing the marriage gap? "Has homosexual union hurt your marriage?" (This is a favorite question of the same sex union lobby.) Can anyone deny that it is hasn't? There may be complex causes, such as women becoming high income achievers and deciding they don't need a man around the condo. And some young people, particularly young men, prefer the sit-com life. They play at life in different domestic arrangements. They signal they aren't ready for the big stage. They have more options.

The new living-in arrangements are not limited to the young. The phenomenon occurs in many age groups. However any redefinition of what constitutes marriage has to affect the societal aspect of marriage. Calling same sex unions "something close to marriage" denies the original purpose of marriage.

The intent of marriage was to see to the birth and rearing of children. If marriage is mainly about children and what benefits them, something is going off the tracks. Stop worrying about whether it takes a village. Most people believe children primarily need a mom and a dad.

One of the new societal pressures is the growing rate of out-of-wedlock births. When 41 percent of all births are to unmarried women, we have a social tsunami in the making. A birth quake, if you will. Instead of "baby makes three," we have "baby makes two."

Further, if marriage is about reproduction, it is also the stage for learning what it means to be a mother and father. We learned from our parents the examples of devotion, self-sacrifice and partnership required to take care of a family. Often we may have not appreciated these efforts until years later -- the years when we were tearing our hair out over our own children.

Just a refresher: marriage is a custom and a practice common to all cultures in all ages. A healthy marriage culture encourages adults to arrange their lives so that as many children as possible are raised and nurtured by their biological parents in a common household. It is what keeps parents plugging along, keeping the show on the road.

Matrimony is also a covenant by which man and woman pledge their fidelity in a partnership for the whole of life. The covenant requires that a man and a woman are free to marry, that they willingly and knowingly enter a valid marriage contract. As such marriage is a sacramental commitment to someone outside the self. By entering this state, we will accept the responsibilities of modern society. We are grown-ups and ready to look out for children and others.

The newest soon-to-be-royally-wed, Kate Middleton, will have our full devoted attention at her wedding. The royals surely have ridden the bumpy road of modern marriage. We care about Kate and every other bride to-be, because we like marriage and being married. We like to see young people assuming their rightful roles. Therefore we rejoice in every bride and groom, royal for a day, who walk down the aisle and take their vows.

Kevin and Marilyn Ryan edited "Why I Am Still a Catholic" [Riverhead Books, 1998] and live in Chestnut Hill, Mass.