Follow up to this post. Some examples of how to go about it.
High up in the tall mountains where the air is bitter and thin and the snows do not melt there live the Root-Folk who farm the starchy tubers and herd the great hairy yaks. The Root-Folk organize themselves into clans based around their stepped farmlands, essentially being large familial units.
Roles are gendered and split. Men do the work of farming the tubers, repairing structures, and crafting wood. Women do the work of herding the yaks, weaving the wool, and raising children. Both men and women do battle against the other clans.
Traditionally there are two sorts of marriage, that for the purposes of conceiving and raising a child, which lasts as long as the two parties agree to raise said child together. And that for the purposes of inter clan alliances, which lasts as long as the good graces of the two clans does.
However in both cases partners are allowed, and indeed expected, to keep lovers of either gender. Both forms of marriage are more akin to mutual agreements towards a goal (the first being raising a child, the second being an alliance) with other relationships freely permissible.
Among the Kulnites of the great river cities when a parent is pregnant they will preform a specific ritual to ensure the preferred gender of the baby they give birth too. Of course the result is not always exactly what the parent desired.
When this happens it is assumed (even to the parents disappointment) that the gods intervened for their own obscure purposes. Such a child is deemed God-Touched and now has two options in life. When they reach the traditional age of adulthood, being fifteen among the Kulnites, they must choose between joining the priesthood and following their parents craft.
Joining the priesthood offers potentially great wealth and influence but comes at the cost of cutting all ties with their family. A difficult choice to make.
Regardless of their choice, all God-Touched are raised to the expectations of their own unique gender. Not quite woman or man, something all of its own. While either man's or woman's work are open for pursuit, they are expected to walk a fine line between not favoring one or other for fear of angering the gods.
While the priesthood may not sire children without divine permission (granted by the Arch-Priest), God-Touched may lay with those who they please. A freedom not granted to the other genders.
Of course, both of these examples are rather tame and do not even take into account magic and other potential speculative aspects. But they're good examples of how this kind of thing should go.
If you would like this to be regular thing, creating examples of worldbuilding queerness, please leave a comment!