Healthy boundaries help us know where we end and our partner begins. This allows us to separate our actions and feelings from our spouse's actions and feelings. It also allows us to know that we are not at the mercy of our spouse's behaviors or feelings. Even though we can't control how our spouse speaks to us or how they feel, we can control how we respond to their actions or emotions. And of course, this means we can put limits on what we will/will not tolerate and how we want to be treated. Example: Your spouse starts to insult you in front of the children. Instead of engaging your spouse by telling him/her not to yell at you while your children are present, you let your spouse know you will be in the other room if he/she still wants to talk. Of course it's important to address that insulting you is inappropriate behavior especially in front of your children, but what needs to come first is for you to disengage. When you respond by addressing this behavior in the presence of children, you have already allowed it to take place. Our behavior must match what we say or we're not drawing a clear boundary.
Having healthy boundaries also mean drawing a line within ourselves. We should be clear about who we are and understand the differences between who we are as an individual, spouse, parent, career woman/man, and any other roles we may take on. We have separate roles, responsibilities, and expectations in these roles. We also have to keep in mind where one role ends and the other begins. We can't be all of these roles at once, even if we try, so our boundaries remind us where these roles belong in our life.
Lastly, healthy boundaries in a relationship allow us to separate our partner as a person from us. Our spouse is not an extension of us, they can't read our mind or our feelings, and they are not here exclusively to meet our needs. This means that they are allowed to have their own opinions, feelings, and problems. Their opinions, feelings, and problems are not a reflection of us, but rather a reflection of them. Having this boundary allow us to be more respectful and empathic towards our spouse when they are struggling or disagree with us. Example: Your spouse makes a comment about how cute and personable the waiter/waitress is. Instead of seeing this as an attack/insult on you, you comment back that the waiter/waitress is personable but not "your type". In this situation, very easily we can interpret our spouse's comment as a comparison to us. This then sets off bells and whistles in our mind that makes us defensive, when in reality our spouse is merely stating his/her opinion (separate from what we think). Now if you're thinking that this kind of behavior, if tolerated, will contribute to your spouse cheating or flirting with others, then what you must realize is that those behaviors require their own set of boundaries. (More on this topic in a different post).
In life there are boundaries we can see, like the fences around houses, the toll booth at a bridge, or the concrete barriers on freeways, and there are boundaries we cannot see. Boundaries of the heart, mind, and in our relationships cannot be seen. But they are there and we need to know exactly where they lie. Unless we know where our boundaries lie, others will not know where they are. So it's our responsibility to recognize and enforce our boundaries. Boundaries allow a healthy separation between partners but also give us opportunity to grow as a couple.