Given that Zalanthas is a place with broad attitudes towards sexuality, it is common to see Zalanthans have multiple sex partners. While your character may be in a monogamous relationship with another character, understand that as a commoner, this does not deserve (and should not get) formalized recognition by the powers that be. Your character also should not expect anything for deciding to limit his or her current sexual focus to one person. Any commoner relationship is not formalized. This means that there are no such things as inheritance laws governing who gets your character's things if they die, nor are there divorce laws concerning who gets which half of things if the couple splits up. Zalanthan commoners are NOT highborn, and this is one area in which that should be very clear.
So, my question is why monogamy among commoners the default? Why isn't polygamy more of a default?
Discuss.
Good topic.
Even though I am entirely monogamous in real life, and not at all a polygamist, I have researched the topic due to interest in roleplaying it correctly, and I've known people IRL who actively practice it. Since it seems so rare in the game, I feel that it is important to represent it and so almost all of my relationship-eligible PCs are polygamous.
It's very difficult in practice for twofold reasons: one, the extreme bent toward monogamy in game, and two, because often I find that players don't necessarily understand or know how to roleplay polyamory.
In a world like Zalanthas, having large family units of purposefully chosen people who are all in mutually agreeable polyamorous relationships would be a huge boon, due to the harshness of life, the frequency of death, and the ability to pool resources and take care of each other's children and living situations.
This does NOT mean "sleep with whoever and if one of your partners doesn't like the other partner, they're just being jealous and bad at polyamory". This does NOT mean "everybody's always happy together and there's never any jealousy, tension, or push-pull between partners".
It does mean that generally, in poylamorous relationships which are healthy and are working out, there will be open communication and a lack of possessiveness over your partner(s) - heck, even an expectation that your lover(s) will have other lovers. This shouldn't be seen as diminishing the connection between your character and their lover(s).
It's also codedly difficult to live together in more than a 2-person unit because of the limitation on PCs-per-rented-room. I'd love to see that opened up so that broader varieties of living situations can be explored.
I find the whole "killing your lover's lover out of jealousy" to be a horribly OOC and western-world influenced practice and in almost all situations, ridiculous. In rare situations I can see it making sense, but it's far too common.