How is Gawain's journey into a magical place also a psychological quest?

I think there are a lot of questions about human nature that transcend Arthurian chivalry. There are psychological questions about telling the truth, love, sex, honor, and the inherent desire to live. The tests that Gawain must pass are organic to the male psyche juxtaposed with his vow of honor. Should Gawain have told the Green Knight about the encounter with his wife? Was withholding information such a bad thing after all? These are questions to do with the human psyche as much as they are plot points.