Based on the narrative tone and themes present in The Odyssey, the most reasonable prediction about Odysseus and Penelope's future relationship is:
They will resume their marriage, but they will feel estranged because of their long time apart.
The story emphasizes the emotional and psychological toll of Odysseus's long absence and Penelope's struggles during that time, suggesting that while they may eventually be reunited, the years apart will create challenges in their relationship.