In that classic Bible passage on marriage (Eph. 5:21-33) so often used, or alluded to in the marriage ceremony, the narrative closes with the admonition, "this is a great mystery, but it is an illustration of the way Christ and the Church are one." (vs. 32 NLB) The mystery would appear to be, from the preceding verse, that two married people could somehow become one, in thought, purpose and action. Obviously it is a picture of the complete unity within the Godhead which translates into the unique relationship of Christ and the Church. Further, from what we read here, it is equally the ideal that God intends for marriage.
Is it conceivable that two, previously individual persons, especially as products of our pluralistic culture, should, or could, become essentially one? The injunction (vs. 31) suggests to me that neither of those persons is better equipped or more divinely entitled to lead the other, but each, as they acquiesce to the other, for the higher purpose of oneness can achieve that glorious ideal.
Having said that I now come back to the thought of mystery. The Bible definition of mystery suggests something that is veiled, hidden, secret or couched in parable. The theme of mystery occurs repeatedly throughout Scripture beginning in the book of Job (chap. 11 vs.7). Zophar asks Job, "Can you solve the mysteries of God? Can you discover everything there is to know about the Almighty?" God is a revealer of mysteries for Daniel the prophet (Dan. 2:22). Jesus Himself is said to always speak in parables and thus fulfil OT prophecy as He, "explains the mysteries hidden since the creation of the world." (Matt. 13:34,35, cross ref.to Psalm 78:2 NLB)
Is it just possible that one mystery hidden since creation is that God's intention for married humanity is a oneness based on equality and mutuality, as opposed to hierarchy? In hierarchy the husband leads and the wife submissively follows, in respect to a supposed divine ordering or fulfillment of a God ordained role. The Living Bible, erroneously I believe, paraphrases it that a wife should simply, "... fit in with her husband's plans." (1 Peter 3:5 LB) By contrast, in a mutually submissive marriage, "each submits to the other out of reverence for Christ." (Eph. 5:21 NLB) Both see the greater good of being united together in thought, purpose and action and strive for that ideal mutually. No one person has the final say by virtue of gender. Each considers the other as heirs together of the grace of Christ (1 Peter 3:7).