He has no companion, no soul mate, with whom to fully share his life. He has met every animal from the antelope to the zebra, but none of them satisfy the need that he feels, the need that God recognized before Adam could even give that need a name. Woman is the result. When the man wakes up, God brings the woman to him. The reader is allowed to visualize Adam rubbing the divine anesthetic out of his eyes as he encourages them to focus upon this wonderful gift which answers the need he felt but only half understood.
Man is thrilled and somewhat inspired.
He creates an impromptu Hebrew poem in v 23. In that poem he reveals his delight with what God has done. His poem makes clear how much he has longed for a true companion. Adam finally sees and knows that for which he has achingly longed. Notice also that this poem makes clear his sense of oneness with the woman given him by the Lord.