Which has nothing to do with anything, except your personal feelings or your personal church members, the Mosque, or the Gay Church of the Goats may have different internals, it isn't law.
You do mention what should be a well known point though, people can and always could, call whatever they wanted, "marriage" between themselves or their group or within their church, the Mormons do today for instance they marry dead people, but it isn't legal so who cares?
Society and the government has to know what a legal marriage is.