NENA O'Neill wore a black sweater, eyeglasses dangled from some sort of beaded string, a nice figure, her hair streaked with a gray, may-be 55 years old, but hard to tell. All in all, a type. She is a type. She and her husband, George, wrote a book called "Open Marriage" which said, more or less, that you could have your cake and eat it too, and now she has written another book and it comes down to something like that old joke about telegrams: Disregard first book.

She does not quite say that in just those words, of course. After all, there was lots in the first book that had nothing to do with sex and infidelity and that sort of thing, and you cannot blame the O'Neills if the title of their book came to mean something else, something they did not mean, something like "swinging." But they did have those sections about sex that one called "Fidelity Redefined." and while they did not recommend infidelity, they did not advise against it, either. In fact, they sort of hinted that it might be a good thing - "rewarding and beneficial to an open marriage," is the way they put it.

Anyway, the book came out in 1972 and it sold something like 3 1/2 million copies, hard and soft cover, and there was something about it, apparently, that struck a chord. It was a book for the times and it said over and over again that you should be honest, straight, out-front, give space, let the other person do their thing, communicate and if you wanted to have an affair, for God's sake, do be honest about it - don't sneak around, make excuses, call late in the afternoon with some cock-and-bull story about work. Simply pick up the phone and say, honey, I'll be a bit late tonight. I'm going to have an affair.

Now O'Neill is sitting in her publisher's office and we are talking of the new book and the old book and life in general. I have just read an article about O'Neill and so I call her up because there is something in the air that I have been meaning to write about. If there is a title for it, it is something like "Sex is Dead" but that, of course, is not exactly what I mean.It is rather that people are now talking about relationships and romance and love and marriage and all of a sudden that is what you are hearing. The person to see now is O'Neill because she is the apostle of what in the popular mind is something else - open marriage. Something about that didn't work.

There were some early signs, some early hints. The communes, the first to proclaim the new life styles, were also the first to report that something was going wrong. Some of them were splitting up and the reason, the cause, was something no one anticipated jealousy. Imagine, jealousy. Who would have thought it?

But still, that was different. That was the kids and the hippies and about drugs and making love to be first person you met in the kitchen. That was not about real people - people who worked and commuted and subscribed to magazines and knew a cuisinart from a blender. For these people, the magazines and books kept saying there were options. Call the options what you will, to a lot of people it was called "Open Marriage."

But there were these couples I knew. They were open. They were honest. They were having affairs. They were not sneaking around (applause), they were lying (applause) they were being honest (whistles). They were being open. Everyone agreed that is was wonderful. The men agreed and the women agreed and I agreed and it all made you wonder. Then they split. There was something wrong. Invariably, someone couldn't take it. It had nothing to do with the head. The head understood.

It was the heart. It was, you should pardon the expression broken.

It all made you think. It made you think that maybe there are things we still don't know about men and women and maybe before we spit in the eye of tradition we ought to know what we're doing. I have some theories and one of them is that one of the ways you measure love is not with words, but with actions - with committment, with what you are willing to give up, with what you are willing to share with no one else.

But who really knows about such things? Who has the facts, the data? O'Neill has the data. She has interviewed all these couples. She has talked to them for her first book and for her second book and now we are talking and I am asking if it worked - did open marriage work. Her responses are couched in soft terms - in "restrospect" and "reevaluate." The picture begins to emerge. Most of the couples did not make it. They are no longer couples. There are things the O'Neills did not count on. One of them is jealousy. Still, she does not say it. She does not come out and say that they were wrong. She does not have to . After the interview, I glance at the press release about the new book and notice it is about something called "the newfidelity."

It's the end of an era.