This is exactly what I was talking about. The individual's communication skills and compatibility FAR outweighs whatever complication is brought by merely adding to the numbers.
Not to mention the fact that monogamous people are not islands either. How their parents, siblings and friends behave with regards to their relationships also affects the "complication factor". If you have a meddling mother-in-law, that's no less likely to fail than a triad with an uncooperative member, and much more likely to fail than a quad made up of 4 adults who are committed to the relationship, committed to polyamory, are compatible with each other and who have advanced communication skills.
Re: Good response
Not to mention the fact that monogamous people are not islands either. How their parents, siblings and friends behave with regards to their relationships also affects the "complication factor". If you have a meddling mother-in-law, that's no less likely to fail than a triad with an uncooperative member, and much more likely to fail than a quad made up of 4 adults who are committed to the relationship, committed to polyamory, are compatible with each other and who have advanced communication skills.