Kraathen of Ehuren, founder of Tremontane, discovered a way to connect every person in the kingdom to the lines of power, allowing them to create tangible bonds between themselves. This was eventually codified in the family bond, which links parents to children, children to siblings, and so forth, and in the marriage bond, which more closely connects two individuals and can provide for the creation of a new family bond.
Most marriages in Tremontane are performed first with the adoption of one party into the family of the other, then joining the two with the marriage bond. Same-sex marriages are given equal standing with traditional marriages.
The family bond provides for strong connections between people, to the point that lengthy sexual relationships with someone with whom you do not share a family or marriage bond become physically and mentally painful. It is not uncommon for Tremontanans to wait to consummate a relationship until their wedding night, especially among the titled families.
Despite (or possibly because of) the unusual structure of Tremontanan families, incest is not only practically unheard of, but abominated, even though technically two siblings could have a long-term consensual relationship with no adverse physical effects.