As I think back on the lengthy epic poem that is The Odyssey, I begin to see Odysseus's journey as a search for those beliefs, relationships, and actions that validate Odysseus's existence. In his first adventures, he seems to think that glory validates his existence. He enters into situations for the sole purpose of naive curiosity and unnecessary blood lust and comes out of them having lost a little part of himself - among other things. He begins to see the futility of these adventures and begins relying on the wisdom of Athena to guide him home. For me, one of the turning points of Odysseus's journey his visit to the underworld. His conversations with fallen heroes, victims of wrongful death, and his Mother awake in him a new found desire for continuance in life, now that he has experienced firsthand the true nature of death and afterlife.
After this point in the poem, Odysseus begins to understand that his survival, and eventual arrival home, will not only heal him, but also heal the loyal and broken people he has left behind - especially Penelope and Telemachus. The encounter with his Mother in Hades reveals the devastating effect his absence has had on those he left behind. From this point onward, he has a clear goal in mind, and stops at nothing to find his way back his loved ones.
When Odysseus finally arrives in his homeland, his plan for revenge has a larger purpose than just vengeance. His purpose is to heal the lives of Penelope and Telemachus through the destruction of the suitors, who poisoned Odysseus's house all the years he was away. Without destroying them, Odysseus could not pay back the loyalty of his son and wife. When he carries out the deed, he is acknowledging the affect his existence has on others, and - in a roundabout sort of way - rewarding them for all they have done to keep his legend alive.
By the end of this epic, Odysseus has stopped validating his existence with glory and has begun to validate it with loyalty to his family and a passionate respect for life. The continuance of his life is no longer in question, for he is strong in his decisions and surrounded by the support of his loved ones in a place he can finally call home.