Ephesians 5:21-24
21 submitting to one another in the fear of God. 22 Wives, submit to your own husbands, as to the Lord. 23 For the husband is head of the wife, as also Christ is head of the church; and He is the Savior of the body. 24 Therefore, just as the church is subject to Christ, so let the wives be to their own husbands in everything. (NKJV)
The church is said to be subject to Christ. So how can the head concept be divorced completely from such considerations?
I would argue it's an analogy with limitations. Again, you have to read this section as governed by verse 21; submission in marriage is mutual
There are mutual elements, certainly, as I noted Jesus' words about true leadership being servant leadership. But Christ is nonetheless leading.
And the mutual submission you speak of does not lead to statements such as "husbands, submit to your wives in everything." The texts are consistently the other direction. And while there is an analogy, showing that the husband should show love as Christ did, there is also a rather short simile, that is more direct:
24 Therefore, just as the church is subject to Christ, so let the wives be to their own husbands in everything. (NKJV)
If Christ can lead without being abusive, then leading is not equivalent to abuse. And the text appeals to wives to submit to their own husbands. Which means that Paul must not have thought that is by its nature abuse, or he would not have said it, and it would not be inspired.
Let's clarify, before moving on to the analogy. Do you voluntarily submit to the leading of Christ? If so, is that relationship abusive?
Yes, I voluntarily submit to the leading of Christ
Then voluntary submission to spiritual leadership is not abuse.
But a husband is not God.
Very true! If it said submit to Christ as you submit to Christ, it would be redundant. But instead it says:
24 Therefore, just as the church is subject to Christ, so let the wives be to their own husbands in everything. (NKJV)
Nor does it say:
Therefore, just as the church is subject to Christ, so let the wives and husbands submit to each other in everything
You say the following.
A one-sided relationship between two mentally competent human adults in which one is supposed to lead, and the other submit, over a lifetime, backed up with the claim that to ever deviate from that is to disobey God, is abusive.
But the text still says this:
24 Therefore, just as the church is subject to Christ, so let the wives be to their own husbands in everything. (NKJV)
I do not see your standard in the text. I do see that it says as the church submits to Christ, let wives be submissive to their husbands.
If your standard is not what God describes, and you accept the text as inspired, then you may need to revisit your standard.
Moreover, we are called to submit to authorities established by God, in a continually submissive, one-directional relationship, for life, and they are not even guaranteed to be just (or in some cases competent). To do otherwise is said to be resisting the ordinance of God:
Romans 13:1-5
1 Let every soul be subject to the governing authorities. For there is no authority except from God, and the authorities that exist are appointed by God. 2 Therefore whoever resists the authority resists the ordinance of God, and those who resist will bring judgment on themselves. 3 For rulers are not a terror to good works, but to evil. Do you want to be unafraid of the authority? Do what is good, and you will have praise from the same. 4 For he is God’s minister to you for good. But if you do evil, be afraid; for he does not bear the sword in vain; for he is God’s minister, an avenger to execute wrath on him who practices evil. 5 Therefore you must be subject, not only because of wrath but also for conscience’ sake. (NKJV)
Peter, in the same letter as his advice to wives, also states this:
1 Peter 2:13-16
13 Therefore submit yourselves to every ordinance of man for the Lord’s sake, whether to the king as supreme, 14 or to governors, as to those who are sent by him for the punishment of evildoers and for the praise of those who do good. 15 For this is the will of God, that by doing good you may put to silence the ignorance of foolish men— 16 as free, yet not using liberty as a cloak for vice, but as bondservants of God. (NKJV)
And in all these relationships of submission, we see that we submit first to God. Peter and Paul could say submit to the authorities. But they both died at the hands of the authorities, because they could not obey when told not to proclaim the name of Christ. The authority of the law is delegated authority, and God's authority trumps it. Peter said it clearly when commanded not to preach in the name of Christ:
Acts 4:17-20
17 But so that it spreads no further among the people, let us severely threaten them, that from now on they speak to no man in this name.” 18 So they called them and commanded them not to speak at all nor teach in the name of Jesus. 19 But Peter and John answered and said to them, “Whether it is right in the sight of God to listen to you more than to God, you judge. 20 For we cannot but speak the things which we have seen and heard.” (NKJV)
You mentioned the case of Vashti. She could not submit to her husband's command if it violated principles instituted by God. We don't know enough about her to determine her relation to the true God. But we can certainly say she was following a higher principle laid down by Him, and was acting holy, in her protest.
I mentioned the case of Abigail as well, who was doing God's will, as David testified, though it meant not submitting to her husband.
In the same way, Peter's command was not without limits. He indicated the wife was to be chaste. She could not disregard the higher authority.
Paul likewise was in prison often for his testimony to Christ. So that his submission to the authorities was only in the context of his greater submission to God.
The submit in everything does not include those things that would go against God's commands. The wife is submitting to Christ first.
And the husband's leadership is not based on his own whim. That is why Paul spells out at such length the nature that leadership should take, comparing it to that of Christ.