Marriage
Marriage is uncommon in elven culture, except among titled and regnant nobles where it is used as a means for formalising alliance. Elven lives are so long that it is very uncommon for lovers to live out their whole lives together. Some particularly devoted couples do marry, but it is a rare event in elven culture. When it does happen, it is seen as a great blessing and particularly large accompanying festivities are organised. It’s not uncommon for a great many elves to gather in one place for such a celebration, further underscoring just how rare such an event is.
Romance and Sex
Elves are more open minded about these things than humans and unfaithfulness is not seen as a problem in and of itself. Sex and intimacy is regarded as positive and experiencing it with someone other than a regular partner is not generally interpreted as something that needs to negatively impact relationships. Human ethical scholars attribute this behaviour to elves’ long lifespans. Very few elves stay in the same romantic relationship their entire lives and distances and travel times on Vatan mean that elves, particularly when they are apart from their romantic partners, tend not to shy away from dalliance. There is no taboo on the subject like there is in almost all human cultures.
Forms of Address
Elves do not tend to use terms that define a single relationship. In particular, terms like mother, father, brother, aunt, wife and other familial relationships are not considered polite as within an elven lifespan defining someone by only a single relationship is not considered to do justice to all the other things that go on in their long lives.
Inheritance
Inheritance of title is defined by the Elven royal charters. A title is generally linked to a subspecies, meaning that a Earth Elven fief is inherited by the oldest Earth Elven child. Children of a different subspecies are not eligible to inherit a fief, unless there is no offspring of the correct subspecies. Even in that case, it can only be temporarily held by a different sub-species and the fief reverts as soon as there is a child of the correct sub-species available. Inheritances only go upwards (i.e. to aunts, uncles, parents, etc) if there are no children who can inherit. This is a practical stipulation as with such long lifespans there’s always a relative somewhere.