yes, but why? slavery was far, far more beneficial in an immediate, material sense to the people who practiced it than "traditional marriage" was/is. to have power of life and death over another human being, and to be able to compel that person with very little cost to yourself to help you satisfy your needs and wants is a massively beneficial thing. so even though we all now recognize it as being repugnantly immoral, it lasted for a very long time until western morality overpowered it because it was extraordinarily useful to people in a very greedy sense.
this just makes the argument defending traditional marriage even MORE powerful. traditional marriage is MUCH less obviously beneficial to people than slavery was. in fact, a very strong argument could be made that it would be MUCH better if we could be free to run around f*cking everything we see for the pleasure of it and to pass along our genes as widely as possible. one can see the allure of seeing some really hot chick with great cans and a tight a$$ walk by, and just knocking her down and trying to impregnate her. the much less immediately beneficial thing (but much more MORAL thing) would be to build a relationship with her, treat her as an equal, pair bond with her for life, raise a family, stick around and take care of them, and NOT be able to knock down and f*ck the next really hot chick with great cans that might walk by. it is benefical for society because it shortcircuits a lot of the violence that arises in the state of nature by running around and f*cking everything you can while fighting off competitors, and it provides huge benefits for offspring who have two committed parents to raise them to maturity, even when that gets hard and when it gets in the way of one of the parties in the marriage running around satisfying their immediate needs with whomever.
slavery was MUCH easier to keep around for a long time because it was so obviously beneficial in an immediate sense, even though it was immoral. traditional marriage is MUCH harder to keep around because in many ways, it actually goes against some of our more primal interests. only a moral society has been able to protect it.