And it requires both partners to regularly recommit to it in spite of all the messages we get from the relationship industry all around us that wants us to buy what it has to sell to make it all better.

The word often used is growth. People and relationships are not static entities. They grow.

But that word is deceiving because we think of growth as a movement in a linear direction through what we are even, at times, told are stages of relationships. Growth sounds as if we should be able to see where we are going, just as babies turn into toddlers, then children, then teenagers, and finally “full-grown” adults.

Even that is an artificial fiction, for it often assumes that there is an endpoint to the growing process. Turning people into “adults” seems to be a goal, as if we have said something everyone knows when we say, “let’s all act like adults.”

Well, adults are the humans who buy all the books about how to have a good self-concept, how to lose addictions, and how to get the love they want. If that’s the end product, we can understand why “adult” relationships are difficult, less than hoped for, and often depressing.

A better word than growth, but harder to adapt to, is change. To the extent that they last, relationships are all, without exception, characterized by change.

And what can scare us is that there is no linear process to change. It’s very unpredictable, more like zigs and zags, and full of surprises.

Relationships aren’t just complicated. They are complex. Complicated means that they are hard to understand.

Complexity means that the changes long-lasting relationships inevitably experience cause us to discover at each new stage something that was not predictable when we began the journey. Complexity means change will come and we will have to adapt our strategies, communication, and lifestyles to it.

It’s going to happen whether we want it to or not. But it doesn’t have to freak us out.

We can work hard to stop the change and resent change when it happens. Or we can commit to change with our partner by committing to on-going communication, expression of how we feel about it, sharing how it isn’t fitting into our “plans,” and openly embracing it.

That’s the basic commitment both partners must make to enable a relationship to be long-lasting without making it feel as if we need to just settle, putting up with a relationship that merely drags on.

Change doesn’t have to mean that the past was bad in the light of the new. It only means that the adventure of discovery and learning further what it means to love and be loved is continuing.

So fulfilling long-term relationships take time. They need attention and nurturing.

Relationships cannot get lost as a less-valuable, taken-for-granted part of a life dominated by careers, making money, and proving to others we are successes in life. They cannot be smothered in neediness and fear of the alternatives.

Long-term relationships must have priority in the lives of their members if they are to be all we want them to be. Whether they are friendships or partnerships, they require our time if they are to be rewarding.

And once we think a relationship has become “what it should be,” it is guaranteed to change. Trying to keep it from changing will be energy wasted that could be put into embracing the change.

Just like life itself, the alternative to growth is death, or, at least, the feeling that our relationship is killing us.

A national resource for information on gender issues and gay/straight relationships for organizations, businesses, educational institutions, and media outlets such as NBC and USA Today, Bob Minor, Ph.D. has been speaking, consulting, and leading workshops for more than ten years.

Bob is author of eight books, and currently Professor of Religious Studies at the University of Kansas. Learn more about him at www.fairnessproject.org.