Not only is this old adage incorrect because experience tells us the opposite, but it is incorrect because it assumes that words are not physical in nature.
When we bless or curse our spouses with our words, we physically move our diaphragms, puff out breaths of air, and move our mouths to produce sound waves. These sound waves travel to our partner, which then hit their eardrums, causing vibrations. These vibrations are then interpreted by their brain, and these messages we transmit day after day, have a physical effect on our partner's brain. We literally change each other's brains as we interaction with our bodies and our words. Thus, when we affirm one another with our words, we physically bless them, and when we hurt one another with our words, we also hurt them physically.
Sometimes, we hurt one another legitimately, such as when we establish a healthy boundary. The other spouse might recognize the value in the boundary, but he or she is still hurt and disappointed. It still hurts, but it is the kind of hurt that, when taken correctly, can actually benefit the intimacy of a relationship. Nevertheless, the hurt is physical. It occurred in a physical way, by way of words, sound-waves, eardrums, and changing our partner's brain.
The more violent aspect come from words that are meant to denigrate, tear down, hurl contempt, or comparison. These words physically harm our partner's brains, and in this sense, it should be noted that all violence is physical. So, if you've been thinking all your life that you aren't a very violent person, but you also tend to criticize your partner, compare him or her to others, belittle them, or simply attack them, then you are a physically violent person.
In this way, we are all physically violent people because we have all hurled insults at others to one degree or another. Our words strike each other's brains just in the same way that sticks and stones strike each other's bodies. Oh, and so many of us think we are off the hook because we don't insult one another. In fact, we keep our mouths shut and refuse to do such things. However, let me tell you about how I harm my wife - it is with my silence. Thus, this adage is true - "The silence was deafening."
When I get angry with my wife, I get silent. It might not be for very long, but it is long enough to hurt her with my language. Yes, not all forms of language are verbal. In fact, as a second language teacher, I know that one of the most important forms of emotional language is body language. Silence is a form of body language that tells our partner we are very angry and yet we refuse to talk. We refuse to engage. You aren't worth me working past the discomfort to communicate with you at this time. To clarify, it is definitely true that we might need to be silent for a time, in order to be able to sooth ourselves, but it is only for a time. Once we are able to calm down, then it is time to enter verbal communication with our spouses. It is at this point that we begin to truly harm our spouses if we refuse to talk. When we give someone "the silent treatment" we are using our body language to do violence to them. Our spouse sees our body language. The light waves hit their retinas, get interpreted by their brain, and over time, our silent treatments begin to reconfigure their brains physically. In short, our silent treatments, just like our verbal assaults are all physical forms of harm, which if done over time, constitute physical abuse as well.
Add to all of this that studies seems to suggest that our emotional status and physical health are connected in many ways, and you can see that emotional abuse over time will affect us physically. Thus, even more reason to remember that our words and body language are physical in nature.
On the side of hope, the more we choose to bless one another, the more we physically restore one another's brains, bodies, and emotional hearts. I believe there is only one way we can begin to turn around and begin to bless one another. We have to believe we are forgiven so that we can have the freedom to try to do good to one another. This is where individuation from our spouse must come. Even if our spouse has a hard time forgiving us for all that we have done, we must decide that we are forgiven, decide to forgive ourselves, and believe we have the freedom to try to do good in the midst of all the uncertainty.
All of us are in different places in the spectrum of blessing and harming one another, but we are capable of doing great physical goodness or harm to one another through our words, our actions, our body language, and our physical comfort. The hope is that we can begin to make repair, whichever part of the spectrum we fall on. That is something that should uplift us!