When I began writing my book Heirs Together I thought it important to define marriage early on. It's always a good idea to determine what one is talking about before one begins talking about it, I thought. So, I began researching marriage historically, what it has been, how we came to think of it as we do today.
What I found is that marriage has been many things throughout history. Only one constant was present, that marriage is a more or less personal relationship between two people, usually a man and a woman. That's all. During most of the history of marriage it has not been a religious ceremony, but an agreement between families and/or the two people involved. It was a practical matter, not a religious matter.
Marriage ceremonies were often very simple, and did not require the services of a priest or religious representative. The church insinuated itself into the business of marriage and turned it into a religious ceremony in which the woman ceased to be a person, but was joined with the person of the husband. That's how we get, "man and wife," not "husband and wife," and why a married woman was known, not as Mary Jones, but as Mrs. John Jones--he was still John Jones, however.
Christians, raised to believe that marriage is some sacred pact with God and that the two people are somehow inseparable, are taught that the metaphor about the church being the bride of Christ has something to do with their own marriages.
Historically, and legally today, a "real" marriage is any marriage that the culture defines as marriage. It's a real marriage even if the couple hates each other, or lives separately, etc., if that is what is legally and culturally considered marriage.
People often think that it's not a marriage anymore if the couple no longer love each other, or one has betrayed the other, or broken their vows. It may not feel like a real marriage, but it still is until it is legally dissolved, because all marriage actually is is a legal designation. The couple has certain rights they can go to court to try to claim and have some hope that those rights will be upheld.
Personally, I believe everyone should negotiate a marriage contract, as is common in certain parts of the world, and which was often done historically. If that is done, and abuse defined and listed as part of what would break the contract and have certain penalties, then there will automatically be some deterrent to abuse, and some protection from it. And clear penalties if it occurs.
The church needs to catch up with the times and be more realistic about marriage and divorce--and abuse. Christians need to know that they are responsible to create their marriages and not be hounded and coerced to stay in them if their best efforts at creating a satisfying one for themselves aren't working.