Traditional marriage has always been between one man and at least one woman. That sounds so awkward when phrased that way.
Traditional Judeo-Christian marriage has always been between one man and one woman for about a thousand years. Unless you were a Jew living south of the Pyrenees, in which case being polygamous was a somewhat expensive option in Spain until about 1400, or elsewhere in the Islamic world until some time in the future.
In traditional marriage, "husband and wife were one person in the eyes of the law, and that person was the husband", until the middle of the 19th century.
In traditional marriage in the United States, marital rape did not become a crime anywhere until the mid 1970s, and did not become a crime in all 50 states until 1993.
The institution of marriage has changed over time and will continue to do so.