The Orchid and the Tide

This story is set in a world where, alongside ordinary distinctions, some people present as "Alpha" or "Omega"- a rarer biological dynamic layered atop the setting's usual social order. Omegas are uncommon and highly prized, often sought after for marriage precisely because of their rarity and their ability to bear children even in pairings that wouldn't otherwise be possible. Aroon is an Omega - a fact his family has always guarded carefully, part of why he's been kept so sheltered his whole life. Sethee is an Alpha, and part of the force behind his instant, overwhelming pull toward Aroon at the ceremony is recognizing what Aroon is before it's ever spoken aloud. A mating bond - marked physically between a pair - is part of this world's tradition, tying two people together in a way that goes beyond the emotional.
This story unfolds during an imagined era of Siam's history, among the wealthy merchant and trading families whose fortunes rose and fell along the river. Tradition governs much of what happens here - dowries, arranged courtships, the quiet authority of family elders - but tradition is only ever the beginning of the story, never its ending.
The novel moves between two points of view, alternating chapter by chapter between Aroon and Sethee, so that the reader comes to know both sides of a courtship that begins as an arrangement and grows, slowly and not always gently, into something neither of them expected.