I remember this one fanfic that had Veelas be mostly chaste despite being some of the most desired creatures.
An idea for the origins of the Veela race chould be this.
I'm a kingdom of Ancient Greece there was a girl, daughter to some King. She had attracted the attention of Eros son of Aphrodite and Ares. Obviously she wasn't as beautiful as his wife Psyche but that didn't matter to him. He attempted to get her attention through disguising himself as a servant but nothing worked out.
He then approached her as Eros himself but she rebuffed him saying that she would only give herself to the man that she falls in love with.
Enraged he cursed her and her bloodline to release an aura that would forever attract the attention of the male race be it human, animal or creature.
Aphrodite seeing her commitment to love took pity on her and made it so that she could at least control it somewhat. Praying to Hecate to undo the Curse yielded no results but Ares was impressed with her ability to stand up to and say that she would only give herself to someone that she would love to a diety of desire. He blessed them with the ability to fight back giving them his blessing of fire and the features of a hawk.