[Please note that there’s a poll at the end of the post! You may need to turn off tracking protection to see it.]
1. Why do you believe what you believe? What would change your mind?
I think that frowning on people who have more than one concurrent sex partner, while accepting as normal that people may have multiple relationships of a different kind (e.g. multiple friends), implicitely demands that one single person should be able to sexually fulfill (and achieve fulfilment from ) a single person, even if they do have sexual desires that do not completely match. We do not require one single friend to be the ultimate games companion, a good conversationalist, a good listener, etc. and we take it as normal that different friends have their roles and that does not make them competitors. Why not with sex? Demanding one single sexual partner ends up exagerating the importance of sex in the relationship, since that partner has to be the sole recipient or purveyor of all the myriad romantic and sexual expectations one has, and paradoxically leads to a more sex-obsessed society. I would change my mind if a proper study showed that, on average, polyamorous people are significantly less pleased (romantically/sexually) with their situation than properly matched (social economic status, etc.) monogamic controls.
2a. A polyamorous person hates their partner’s other partner (their metamour). In a healthy relationship, what would happen next?
Not a big problem: they would arrange their schedules so that the conflicting members of the relationship did not have to meet.
2b. A polyamorous person has a date scheduled with their primary partner, but their secondary partner is in the hospital with an emergency and needs support. In a healthy relationship, what would happen next?
The same that happens when some other emergency (an unexpected work meeting, a parent falling sick, etc.) happens to a monogamous couple: the emergency takes precedence, but care must be taken to ensure that this is a one-time thing and that the primary partner doe snot end up being repeatedly neglected due to freuqent “emergencies”. If “emergencies” become frequent enough to derail commitments with the partner, that is a sign that something is wrong with the time-management or with the worth that the person assigns to the relationship. This is the same regardless of the nature of the relationship or of the “emergency”.
3. What would happen if 90% of people in a society were polyamorous?
Hollywood/TV dramas would either (on the lower end) focus on exaggerated tales of jealousy or (on the higher end) stop being focussed on romantic triangles,etc. and would probably start focussing on less-escapist, but more socially relevant storylines regarding care for people-as-people rather than people-as-“wish-fulfilment-romantic-fantasies”. I expect the circle-of-concern of most people would also expand and lead to a more caring society.
Marriage law would lose its underpinnings and be substituted by flexible contracts involving domestic partnerships with no limits regarding number of people, gender, etc. This would be a good thing because it would decouple the state from people’s most intimate decisions and would definitely get governments out of people’s bedrooms.