Relationship anarchy refers to the practice of not following societal norms or society-dictated rules when it comes to having a relationship. The couple or multiple people involved in the relationship decide on defining their relationship, as well as regulating personal expectations and actions. People who abide by relationship anarchy do not identify themselves with the usual labels, such as 'in a relationship,' 'friends,' and the like. Likewise, the relationship does not need to be distinguished as sexual, platonic, or romantic.
More About Relationship Anarchy
A relationship anarchy is governed only by terms agreed to by the people involved. The key is that all parties agree on the definition and terms of the relationship. It is not anarchy if only one side of the relationship knows about what going on. That's just being inconsiderate of the feelings and expectations of others.