Separation of Church and State.

Government has a role, a very necessary role. In general that role is to address the large national requirements for managing a country's internal structure and external safety.

In general, a Government need not be distracted from that larger purpose in deciding what the individuals of that nation are doing in their personal private lives. As long as things are consensual and respectful, individuals should be able to love each other how they choose. And that includes how many people they choose to be with.

From an historical perspective, more cultures were polyamorous than monogamous. Most creatures today are, simply put, “polyamorous”.

From a biological point of view, polyamory increases the genetic diversity of a species., therefore strengthening its genetic pool. While monogamy restricts genetic diversity and limits genetic variability, which is needed to adjust to external pressures - like pollution.

If a person chooses to limit themselves on a bases of religion, love, simplicity or for some other reason - that is their right. However, a government should not be distracted from its national responsibilities in deciding who gets to be with whom.

For that, governments can put money towards education and trust well trained teachers to educate people to make informed decisions for themselves.