I've not attempted to read much into Horace's background; probably it would be good somewhere to list some links to good references to his life beyond just wikipedia. Surely there will be some articles too which explore specifically his Epicurean aspects. I believe I remember reading that Horace had perhaps been a soldier on the Republican side at Philippi? OK:
"Rome's troubles following the assassination of Julius Caesar were soon to catch up with him. Marcus Junius Brutus came to Athens seeking support for the republican cause. Brutus was fêted around town in grand receptions and he made a point of attending academic lectures, all the while recruiting supporters among the young men studying there, including Horace. An educated young Roman could begin military service high in the ranks and Horace was made tribunus militum (one of six senior officers of a typical legion), a post usually reserved for men of senatorial or equestrian rank and which seems to have inspired jealousy among his well-born confederates. He learned the basics of military life while on the march, particularly in the wilds of northern Greece, whose rugged scenery became a backdrop to some of his later poems. It was there in 42 BC that Octavian (later Augustus) and his associate Mark Antony crushed the republican forces at the Battle of Philippi. Horace later recorded it as a day of embarrassment for himself, when he fled without his shield, but allowance should be made for his self-deprecating humour. Moreover, the incident allowed him to identify himself with some famous poets who had long ago abandoned their shields in battle, notably his heroes Alcaeus and Archilochus. The comparison with the latter poet is uncanny: Archilochus lost his shield in a part of Thrace near Philippi, and he was deeply involved in the Greek colonization of Thasos, where Horace's die-hard comrades finally surrendered."
Also I see there is a reference to Suetonius' "Life of Horace" (Latin, but we need English ) Loeb (limited access)
Here we go - Life of Horace at LacusCurtius