A couple comes into the office with an all too familiar complaint. They are approaching 30 and have been living together for about 3 years. She (it's usually the woman), wants to get married. He (it's usually the man) doesn't.

He says, "We're happy as it is. Why should we get married? It's just a piece of paper and it won't change a thing."

She says, "We decided to live together to see if we are compatible. We are. It's time we got married."

It's not just a piece of paper. (If it were, there'd be no fuss about getting one.) Studies show that couples who live together before marriage are much more likely to divorce later. Living together doesn't guarantee happiness. It doesn't help people get to know each other better. It doesn't even tell the couple much about what it will be like to be married.

It's all about what's under the surface. When a cohabiting couple fights, they both know that they have a back door out of the relationship. She knows if it gets too difficult, he can leave. He knows that she knows and vice versa. To avoid hurt or separation, each person will pull back from a fight that might expose them and/or the relationship to flaws that they find too frightening to confront, much less fix.

Paradoxically, the very thing that protects a cohabiting couple from hurt also can "protect" them from a commitment to each other. The normal conflicts that occur while making a life together become reasons to leave rather than exercises in compromise, accommodation and tolerance. Married couples who have made the promise that they are in it for life have much more invested in working through a problem than in denying it or avoiding it. And it's in the working through that the relationship matures and grows stronger.

The very prospect of the difficulty of the divorce process, legally and emotionally, sometimes can help keep a couple together long enough to heal. If the relationship is essentially sound but going through growing pains, family, community, and legal support for staying married can often get them through.

Breaking up a living together relationship, however, involves no court battles, no financial obligations, and few moral judgments. Parents and community may find it sad or mystifying that the couple split but they also are more willing to accept it than they are to accept divorce. Other than a few "I told you so's", from those who didn't want them to live together in the first place, there is usually little comment outside the couple. If the couple was unwise enough to make a commitment to a child before they made a commitment to each other, it is more complicated. But deep inside each knew that they might well end up as split parents and protected themselves accordingly. Usually the child and Mom make one household and Dad fades into the background. Life goes on.

There are good but painful reasons why people choose to live together rather than marry. Children of divorce often find it difficult to make a commitment to a partner because they don't want to put themselves in a position where they might have to go through the break up of a family - again. It simply follows: If you never marry, you can never divorce. Depending on how their parents handled their marriage and divorce, these young adults bury their fears about repeating the process under rationalizations, philosophy, and angry refusal to get into a position of vulnerability with another person.

Adult children of divorced parents don't have an internalized sense of what a long term marriage means so often don't have a compass for negotiating a long term relationship. They haven't the foggiest idea that deciding to permanently couple can be very freeing because the energy taken up by the search for a mate can now be redirected to making a family, friendships, and career. They don't know how safe it feels to fight when you know that a fight doesn't mean a split. And they haven't had the experience of a relationship getting stronger because people were committed to growth as a couple (and as individuals within a couple) rather than in individual protection.

And some people choose to live together rather than marry just because they can. In a culture that increasingly does not attach shame to a live-in relationship, couples can get the benefits of sharing household tasks, some of the expenses, and companionship without having to project very far into the future. It's a roommate situation with sex added. Men seem to have an easier time with this long term than the women do and it's usually the women who eventually either try to make the arrangement into something different or call it quits.

When cohabiting couples come to me looking for advice about what to do next, I often suggest that they find separate apartments and look at each other anew. Meanwhile, we take a look at what it is that they hoped to accomplish by living together and whether it is working. Often enough, it isn't. The fears and protections that have been in the way of commitment haven't been addressed. It's only when they can support each other through those fears that they can move toward being a couple.

Dr. Marie advises:

If you are living together but are unhappy with the arrangement . . .

• Be honest with yourself about why you decided to get into this kind of arrangement. Be equally honest with yourself about why you think your partner chose living together rather than marriage.

• Communicate about your fears. Find ways to reassure your partner. (See article entitled "Commitment".)

• Separate and take a fresh look to discover if you and your partner want to marry..