There is good communication which is vital to any relationship's good health and vitality. There is, alas, another kind of communication which poisons even a potentially good relationship.
Of course, the word "communication" usually connotes the equitable, good kind, in which there is willingness to understand and afford validity to each other, even when differences of opinion or perception are present.
The good kind includes give and take, showing mutual consideration, respect, caring employing all the wondrous benefits of humans in exchanging our thoughts and feelings as effectively as we are able. If that's not essential to the health of a relationship and its participants, I don't know what is! It does take both participants in order to exist, however, as well as verbally. Silence is even a kind of communication.
It's not merely verbal. Actions, expressions and body language express our regard for another person, and are all part of communication. The negative kind of communication is expressed by all these methods, plus by silence.
Consistently positive elements maintain relationship health, which an occasional goof can't destroy. But consistent negative "communication" can and will destroy it, whether it is expressed by one or both participants.