"It will not be we who reach Alpha Centauri, and the other nearby stars, it will be a species very like us, but with more of our strengths and fewer of our weaknesses, more confident, far-seeing, capable, and prudent. For all our failings, despite our limitations and fallibilities, we humans are capable of greatness."-Carl Sagan
Posted by: Doctor Jensen
Posted by: I Nebula I
Posted by: HipiO7
One cant live without the other.
They have basically become one.
John sees Cortana as a useful piece of UNSC kit, basically she's in the "irreplaceable tools" section of John's mind. Perhaps early on. But months of being together (eventually years when Halo 4 hits) has brought them close.
Compared to decades fighting with his Spartans, I don't know. Maybe he holds on to Cortana because he seen Halsey as the only link to his past that makes him happy in a weird way
Who knows.