Originally Posted by autistichalsin
This, plus also, it's DND canon that wood elves are not monogamous by default. If it makes sense for ANYONE to be poly, it's the wood elf.
Well, people say it is not canon. Here:

Originally Posted by Amirit
(Has to say it again about the "lore of wood elves". Their polygamy nature is not a DnD rule or lore. It was mentioned in one DnD-related novel. One. Once. Larian can absolutely make it part of their game but since it does not apply to anyone else in the game world, it does not look like a rule there either. More like Halsin's personal nature.)

Originally Posted by JeyFrey
Based on this article on the Forgotten Realms wiki (see Personality) this seems to be something that has been thematised in the novel The Summoning, though to be fair, I never read it and am not sure of it.

This is what the wiki article says:

Wood elven romantic and sexual relationships were often polyamorous in nature, members of the race freely engaging or ceasing relations with new partners. Feelings of jealousy and possessiveness were as a result viewed by the race as reasons for teasing or mockery. As a result of these perspectives on love, high elves often believed that any relationships engaged with wood elves would be destined to fail from the start.