> felt obligated to keep alive
Back to the point made before, relationships are being defined as feelings like feeling obligated to keep it alive. You are kind of bottling the definition of relationships to just "feelings" and ignoring relationships formed with explicit terms, like marriages are made.
Some relationships are defined by blood and some by a contract (like a marriage contract) and others by history. Some relationships are friendly. Some relationships are self-serving and when the needs are met or if they change, the relationship disappears. Virtually all non-blood relationships are bound by an implicit "trade". If the trade ceases, the relationship disappears.
The rest of the points you made are lost on me. I don't know which direction you are going in. It might be etiquette and courtesy, which are governing principles of respect. And respect is also a form of trade.