Interesting analysis by @jbuffyangel
THIS IS IMPORTANT! If Oliver is truly going to be a ‘hero’ he has to allow his heart to play a part in who he is as the hero/The Arrow (he has to have compassion).
Felicity holds Oliver’s heart. If Oliver’s heart is crucial to The Arrow, and Oliver Queen is Oliver’s heart, then Felicity is the foundational support of both Oliver Queen and The Arrow because she holds them together within the same man. She holds his heroism, his inner goodness, in safekeeping.
Oliver Queen (Oliver’s heart) loves Felicity and needs her in his life in order to be happy as a person. But in order to be with her, Oliver has to be a better man than he once was. Otherwise he’ll only hurt her.
Oliver needs The Arrow (Oliver’s mind) in order to be a better man as Oliver Queen. Oliver never behaved ‘ethically’ or ‘morally’ until he started becoming The Arrow on Lian Yu. Before the island, Oliver continually lied, cheated, and took advantage of people; he was thoughtless and careless.
On the island, Oliver began to understand that there were more important things than himself. It wasn’t an overnight change, but everything that happened on the island made Oliver realize the possibility of being a better person.
Oliver Queen and The Arrow may have taken huge steps back from that realization in the intervening years, but Oliver has steadily taken steps forward in the last two seasons, due in large part to Felicity drawing out and holding his ‘goodness’ in safekeeping. Felicity makes Oliver a better man and a hero.