You know that couple—the one that checks each other’s email, answers each other’s cell phones, and formulates opinions as a pair ("We're so over Will Ferrell!"). Maybe—horror of horrors!—you've even been in that relationship. Regardless, it's important to find a balance between independence and intimacy. That’s why we asked Jane Adams, Ph.D., author of Boundary Issues: Using Boundary Intelligence to Get the Intimacy You Want and the Independence You Need in Life, Love, and Work, to explain why fences can sometimes make good neighbors.

Why do we create boundaries in romantic relationships?
We create them because of this tension we're all born with—the dichotomy between a need for an intimate connection and a need for autonomy and independence. In a romantic relationship, that early, very basic human need for union—an artifact of the relationship with our mothers—is reactivated.

What are healthy boundaries? Unhealthy ones?
In a romantic relationship, it's that moment of union—when we let down the barrier between ourselves and others—that is considered healthy. On the other hand, we can't live in that unguarded way all the time because we lose our wholeness, and then we’re only whole in the presence of the other.

How do boundary styles vary with gender and age?
All the research shows that women have thinner or more permeable boundaries overall than men do. Also, boundaries tend to get thicker as we get older. The boundaries between impulse and action are missing in children. As adults, we learn to think about our impulses and make decisions about whether we’re going to act on them or not.

How important is it to have matching boundaries in a relationship?
It's not that important—although the most adaptive position is if both of you have moderately permeable boundaries. What is important is to understand how your boundaries differ from your partner's.

Do you have an example of how this can play out in a romantic relationship?
Sure—take Patty and Greg. Greg's boundary style is more permeable and less flexible than Patty's. So when she's wrapped up in a work project, he feels shut out and even threatened. That’s when he picks fights about money, her housekeeping, and the in-laws. But the conflict isn't about those things; it's about him feeling distanced by her. She's learned to head off those conflicts by reassuring him of her love—she'll put notes in his briefcase or send him flowers at work.

Do people carry their boundary behavior from relationship to relationship?
I think they do. You find women who say they’re never going to open up to somebody and get hurt that way again, and they go right into the next relationship and do the same thing. Unless there's awareness, boundaries tend to stay the same.