Our research involved talking to people in the same situation you’re in. They were asked about their ambivalent feelings and their partners’ positives and negatives. They were followed over time, during which many tried to solve their problems (and many were successful) and many ended their relationships.

Then we tried to figure out what made some people say overwhelmingly this made me happy I left and made other people say overwhelmingly this made me happy I stayed. These answers evolved into the questions and guidelines that form the backbone of this book.

The ultimate test of all this is in one-on-one work with people like you. Only when these sturdy truths make sense for a wide spectrum of individuals can any of us feel confident that real help is available.

To be fully responsible to your uniqueness, I have to be very careful about telling you what to do. But if I’ve found deep and powerful truths that hold up for large numbers of people, truths that have been validated over and over, don’t I also have a responsibility to tell you these truths? I can’t tell you what to do, but I can and must tell you what I know. I can’t predict the future, but I can tell you the odds.

It’s what trusted professionals in our lives do all the time. For example, about ten years ago I went to my dentist with a dull, intermittent toothache. He said I’d need a root canal to save the tooth and eliminate the source of the pain. He said that without a root canal the pain might go away for days or months or maybe even a year or two but it would come back and it would get worse. A root canal was the answer.

“How do you know for sure?” I asked.

“Well, I don’t know for sure,” he said. “Everyone’s unique, but this is how things will probably work out in your case because, based on what I can see, it’s how things generally work out for people in the kind of situation you’re in.”