Marriage

Marriage isn’t a very common custom in Exorsia outside of Humans, Dwarves and Halflings. It was traditionally a Dwarven custom that allowed people to join the Clans or Houses of their lovers by limiting political disputes or fractured loyalties. It was then co-opted by humans as a way to link noble houses for alliances, and then later developed to symbolise a promise of love between two peoples for the long term.
While it is now common practice as the final step in a Human or a Halflings romantic relationship, this custom is far less practical for peoples that live four or more times longer than humans and in inter-species relationships where being stuck in a long term bond is restricting and unlikely to persist. Because of this many peoples with long lifespans are more likely to practice polyamory.