I’ll go with Aegnor, son of Arafinwe (or Finarfin, however you like). In the Silmarillion, he is Arafinwe and Earwen’s third son (fourth if you believe Orodreth is his brother, rather than his nephew).
Anyway, Aegnor, whose name means “fell-fire” (Aicanaro in Quenya) was born in Tirion in Aman, and when the Noldor reached Middle-Earth, he was lord of Dorthonion alongside his brother Angrod (father of Orodreth, if like me you go with the nephew route). He was in love with Andreth of the House of Beor (a human woman) but never married her, even though they both loved each other. Aegnor was killed in the Dagor Bragollach (Battle of Sudden Flame) in FA 455.
Ok. That much is all canon.
In mine and my co-writer’s headcanon, I can’t mention Aegnor without speaking of Galadriel, since he is Galadriel’s twin brother. Still, he cleaved to his elder brother Angrod more. Galadriel, born Artanis, followed her elder twin and his favourite brother, wishing she had been born a ner so she could do the things it was proper for neri to do and be like her brothers. Aegnor teased her for believing that nissi could be like neri, and even their amille Earwen stuck her with the name “Nerwen”, male-maiden, much to Aegnor’s amusement. Much to Aegnor’s dismay, as well as her proficiency in typically male activities, his twin grew to be the taller of them. He was quite upset by that.
But deep inside, past the mocking, Aegnor cared very much for his beloved twin. He saw that his path was not hers, yet they both grew to love those who others would find inappropriate (he a Mortal, she a Sinda prince). Aegnor’s thoughts often strayed to Nerwen – for he could never think of her as “Galadriel” or even Alatiriel, the Quenya version of the name – and when he fought in the Dagor Bragollach, it was with Nerwen’s name on his lips that he died, and a wish in his heart for her to know happiness.