Had an old Merriam Webster dictionary circa 1990 and here is the definition of marriage: the act of marrying, or the state of being married; legal union of a man and a woman for life, as husband and wife. I believe this is still one of the definitions but they have now added same sex. And of course that is the definition of marriage going back thousands of years.
I am sure you would agree with me if they changed the definition of an apple to: a globose berry with a yellowish to reddish-orange rind and a sweet edible pulp. I think you would agree with me and say, hey, that's not an apple, that's an orange! Or maybe like the defintion of marriage you would start calling an apple an orange. Makes as little sense as calling same sex couples married......