The story of Adam and Eve has nothing to do with marriage per se. It is a story about the beginning of a nation...Israel. So, God chooses a guy, Adam. Gives him a wife that he must regard as part of him, aka "the nation." They must work together to establish their landrights, aka "garden of Eden." Then, they must fill that land with their offspring, aka "little Israelites." It is part of the narrative in establishing a 'divine right" of "manifest destiny" similar to what every nation has done before and since the Jewish nation.
SOP