The Concept of “The One” in Song of Songs

Is the concept of "The One" in human love really true? If it is, how can we know who "The One" is? If it isn't true, then how can we make sense of God's sovereignty and predestination and the Christian commitment to monogamy in relation to this realisation? Has God prepared a partner for us in advance and, if so, how can we have any freedom in this area? If the concept of "The One" is not true, then how should we interpret the passages within Song of Songs which seem to suggest the truth of this concept?