The speaker, whose rosy fingers can be found tracing out the hour of daybreak, would be Aurora/Eos? And then, of all her loves, who is most dear? Three possible ones: Astraeus, lord of the dusk, with whom Aurora had the most children (for what that's worth!); tragic Tithonus, kidnapped by Aurora and granted an unnatural longevity from which he begged to be released (again: be careful what you wish for!); and Cephalus, with whom Aurora had a brief infatuation with terrible consequences for poor Cephalus. Of these, the one most likely to muse beneath Aurora's bower seems to be Tithonus.
Tough one, Augusta. Beautiful but tough -- like Livia I guess. Am I close?
After such a wonderful expositon, I only wish you were right, MPC! Let me give you a hint. He is scouring the sky to learn the hour but not during the day.