Birds do it. Bees do it. We all do it. We’re programmed to spend a good portion of our time looking for and longing for a loving partner. But once the euphoria of early love fades away, what was so simple becomes very, very complicated. Marriage is not for the faint of heart.

In her new book For Better: The Science of a Good Marriage (Dutton, $25.95), Tara Parker-Pope explores spousal dynamics with a keen eye on the facts of human interaction. She presents an easy-to-read compilation of research conducted by well-known experts in the fields of love, sex and wedded bliss. How do we fail our partners? she asks. How can we lift them up? What makes or breaks the bonds of matrimony?

Not surprisingly, she finds that sex and wealth are key players; the happiest couples have frequent sex and few money worries. But most partnerships are solidified by a series of gestures and attitudes that, over time, evolve into either distancing and contempt or intimacy and contentment. Parker-Pope says it’s the way we fight, not conflict itself, that shapes our feelings towards one another. And each partner’s rendition of the “how we met” story is a deeper tale than we might imagine, especially when the storyteller’s altered perspective reveals the true state of the marriage.

Social scientists have studied all aspects of marriage: attraction, commitment, parenting, power struggles, gender wars, division of household labor, and health impact, among others. Parker-Pope presents their scientific data in her familiar, comfortable prose. Some of the information is repetitive; some of it you may have heard before. But much of it will surprise you. For example, she discovers that the notion that 50 percent of marriages end in divorce is a myth, with current studies indicating that marriage is stronger now than it has been in years. Another interesting fact: couples who argue often have more stable relationships than those who don’t. And same-sex couples, who tend to have similar conflict styles, fight more fairly, and with less hostility, than opposite-sex couples.

Many chapters include quizzes to guide husbands and wives in assessing their own relationships, breaking the information flow into easily digestible chunks and giving the book a more magazine-like feel. The final chapter, “The Science of a Good Marriage: A Prescription for Marital Health,” presents clear lessons about what it takes to reinvigorate a union that’s gone stale.

Parker-Pope doesn’t play psychologist.  Her analysis doesn’t include theories about why we choose our spouses beyond physical attraction, or why we are so often infuriated by those we love. There’s no plan for staving off the good intentions of interfering in-laws, and no instructions about how to keep passion in the bedroom.

What she has done is produce a research-based explorer’s guide to the often mysterious world of marriage—a valuable resource for those of us who want our partnerships to be long, steady, and true.