Marriage is a union of a man and a woman becoming one.
In Ephesians 5, there is much on the Church with the relationship between a husband and a wife as an illustration of what it should be like in terms of leadership.
The word ‘submission’ used in many translations has a very bad press and is a source of much disagreement between Christians.
These verses in Ephesians say that Jesus is ‘head of the body’. A ‘head’ seeks to serve the ‘body’ in making sure it functions properly. And for the ‘body’ to work together, it needs the ‘head’ to provide it with the information it needs. Therefore the husband should take the lead in bringing out the best in their relationships and the wife should allow him to do so. All this is based on love, not control.
Hence, the use of the words ‘husband’ and ‘wife’ are two sides of the same coin. It is more about working together, rather than who is in charge. Jesus came to serve, not control. For elsewhere in Scripture, it says we are all equal under God, and we are His children. To me, that means a woman can be a leader in the Church, as much as a man. For we all can receive the Gifts of the Spirit. Our hang-up is because of the non-biblical division of priest and laity, and also over who can give communion. There is nothing in the New Testament limiting as to who can or cannot do things. It is all about character.
And that character should be reflected in a marriage. As we see from above, marriage is about bringing out the best in each other in the context of a loving relationship. But, it is also for the purpose of naturally creating children, and only a man and woman can do that within a loving, permanent relationship, sealed before God in a covenant before His people. Therefore, I don’t believe we can re-define marriage to include any other form of relationship. Children need to understand their sexuality and the limits of when sex can take place ie within a marriage of a man and a woman, for them to grow up as reasonably balanced adults.