The Love that calls for marriage.
I read a piece recently that argued polyamory as being superior to traditional marriage because it tended to result in better character in those participating in it. Traditional marriage breads jealousy and thus hostility and violence. This happens when a spouse has relations outside of marriage. But if this happens in polyamory, this doesn't happen since the point of polyamory is complete openness to experience sexually with others. In fact, instead of jealousy, the partner feels happiness in the other's success sexually. Rather than tending to violence, sex with other people tends to happiness in the case of the partner.
The problem with this view is that it overlooks the case where the partner does not have relations with anyone else. In the case of the polyamorous partner, she must be required to be sad for her dedicated partner for not succeeding with others but not only that she must at all times realize that she has no special claim to any of her partners' affections nor they to hers. Polyamory instills an imperative to be open to providing "benefits" with many partners. She's not even to be dedicated to certain sets of partners. Polyamory tends to a kind of ubiquity of relations to the point where e en friendship is irrelevant. But a traditional marriage understands that partners are partners because they have been chosen. Not only that but chosen with lifelong dedication. Marriage traditionally conceived is an exclusive covenant and promise. When one says "I do", one sets a precedent against predictable future discounting and this assures the partner that right now when and while one is right minded and whole hearted one dedicates to their partner for all of life. This is a kind of precious love. Conjugal family creation specifically calls for covenantal love and thus traditional marriage.
Polyamorous arrangements assume no effort will be made to prevent discounting the future and that everyone involved will simply follow the mood at the time. The aim is to avoid sabotaging the heat of the moment and to mitigate the need to sublimate the libido. In polyamorous agreements, persons volunteer to be mere means. This is not as readily seen as it is in the case of slavery or Old Mormon style polygamy where the man is a kind of king and his wives are like his retainers. In polyamory however you have a kind of original position where several people contract to exchange sexual benefits with each other in the future. This is to grant each other property in the other's bodies but only, though not necessarily exclusively, for pleasure.
So polyamory is only finding a happiness in another's increased utility, like when a friend wins at Lotto. It's not violent but also not much since the ends obtained come and go. But the anger that goes with infidelity is righteous indignation and need not be brute violence. On the other hand, there is no sense of dedicated love in polyamory and polyamory would resist and discourage such love by requiring infidelity to justify the lifestyle. Further, polyamory includes no provision for children. It would have to make special provisions if children are had or desired that would either compromise polyamory or compromise children. This could include sterilization or abortion, so polyamory is not necessarily without it's violence.
The oceanic pleasure of the experience machine of polyamory that constitutes it's "spirituality" is certainly spiritual in the original paganism of the human race. But in the spirituality of western theism the model of religion is marriage. God's people are a "chosen people", his prized possession, the apple of his eye. And he is a "jealous God". In paganism the people find useful deities, but God says, "You did not choose me. I chose you." God makes a covenant with his people and they are thus identified with each other. God's love is unconditional but still exclusive. This is the difference between Eros and Agape.