Few concepts have caught fire in the pop psychology, relationship, and self-help worlds quite like boundaries have. The word has almost become a mantra in recent years: therapists, creators, and influencers alike are using it to advocate for healthier relationships. And rightly so. A boundary can help people reclaim their sense of self, reject outdated narratives about control, and insist on respect and autonomy within their partnerships.

But as it is with most viral ideas, the message has become somewhat distorted. Somewhere along the way, many people began confusing boundaries with rules. Yet as similar as these two things might sound, they actually function very differently. As a result, the rush to rectify old power imbalances has led some individuals to inadvertently create new ones.

At first glance, both the words “rule” and “boundary” seem to serve the same purpose: to protect one’s emotional or relational safety. But in practice, they operate on almost totally opposing principles. Boundaries are about self-governance, whereas rules are about governing others. And when these two concepts are conflated, a relationship can be poisoned from the inside out. Here’s why.

What Is a Boundary?

Despite their sudden popularity in both online and offline self-help spaces, there’s a surprising lack of research on boundaries within the context of relationships. Many studies reference them without ever really defining what they are, which is perhaps one of the reasons why they’ve proliferated so rapidly, to the point of almost becoming a form of well-intentioned misinformation.

One exception is a 2011 study on nurse–patient relationships, published in the journal Human Relations, which defined boundaries in a way that resonates well today: the creation of “an emotional distance or connection” to “manage anticipated, evolving, and felt emotions.”

In this sense, a boundary is a personal limit. Some might imagine it as an invisible line that they draw to protect their emotional, physical, or psychological well-being. This makes boundaries an effective means for outlining exactly what it is that you need to feel safe and respected in a relationship.

What’s crucial to distinguish is that boundaries are a matter of what *you *will or won’t tolerate, rather than what *other people *have to do when they’re around you. For instance, an individual might set the following boundaries:

• “I won’t stay in a conversation where I’m being yelled at.”
• “I’ll have to take some time away from you if you continue to act this way.”

In both of these examples, the behavioral conditions being set are completely self-directed. They’re communicating exactly what their needs are, while also making it very clear what will happen if those needs aren’t met.

For healthy couples, boundaries are always internal, flexible, and self-enforced. This means that they shouldn’t serve to demand that your partner change their behavior, but instead to help them understand what you’ll do if that boundary is crossed. This also makes communication the backbone of a well-set boundary, because even the healthiest one will fail to function if it’s never voiced in the first place.

The most important distinction to note is that boundaries are not ultimatums, nor are they rigid lines drawn in the sand for the purpose of controlling others. They’re expressions of self-awareness and self-respect, which, in turn, form guidelines that help you feel as safe and loved as possible in your relationship.

What Is a Rule?

A rule, on the other hand, is an expectation that one person places on another, with the key feature being that it’s set with the intention to shape or control the other’s behavior. These often echo the same kinds of rules that we were given as kids by our parents: “Don’t do this or you’re grounded.” Only in adult relationships, they might sound like:

Boundaries Essential Reads

• “You’re not allowed to go out drinking without me.”
• “You must text me every hour when you’re out.”

While boundaries are self-focused and enforced through personal action, rules are the opposite. Specifically, they are externally focused and enforced through pressure, persuasion, or punishment. This also means that, by nature, they’re made to be rigid, unilateral, and a matter of compliance rather than cooperation.

This isn’t to say that all rules are inherently bad and restrictive. Some mutual agreements in romantic relationships (monogamy, financial transparency) can absolutely be healthy. However, the key word is mutual. A rule that’s co-created by both partners is a collaborative agreement; a rule imposed by one partner upon the other is just a power play.

Why Confusing the Two Causes Trouble

As research from the Journal of Emotional Abuse explains, boundaries are essential in just about any relationship. Without them, individuals risk becoming victims of boundary dissolution, which refers to the loss of psychological distinctiveness.

This occurs when individuals start losing track of where they end, and others begin, either emotionally or mentally. This, in turn, can lead to confusion about roles in a relationship. In family dynamics, this might look like a dynamic where, either behaviorally or emotionally, it isn’t clear who’s the parent and who’s the child.

But in romantic relationships, it typically looks like one of two extremes. On one hand, it can lead to enmeshment, where partners start taking on each other’s feelings and responsibilities in unhealthy ways. On the other hand, it can lead to a power imbalance: one partner dominates or controls the relationship, while the other becomes submissive or dependent.

However, mistaking a boundary for a rule can create that same power imbalance. Conflating the two weaponizes the language of self-care and therapy; what’s worse is that this is done to justify control. While the word “boundary” alone might sound progressive, misconstruing it with a rule is ultimately regressive. You cannot use vocabulary that was designed to promote autonomy to restrict someone else’s.

A version of this post also appears on Forbes.com.