The problem with 'marriage' is that both society and the government have taken the term 'marriage' and given it a legal definition so that it could be applied when determining who benefits from all sorts of 'secular' rights and privileges, the vast majority of which have absolutely NO religious component to them at all, and if they did, they would probably be seen as running contrary to the 1st Amendment, just that many of these 'rights and privileges' pre-date the Constitution itself.
Perhaps we should adopt the way this is handled in many other parts of the world, where getting 'married', the legal act, and having a 'wedding', often a religious service, or at least one with certain 'religious' trappings and overtones, are two totally different activities. The irony is that for a large number of people in the US, we already have half that system in place today, as many people are married by justices of the peace, judges, or people licensed by the state to do so, such as the 'wedding chapels' in places like Las Vegas. That way, only the 'marriage' part of the procedure would be needed to establish for a couple all of the 'rights and privileges' reserved for those legally recognized as being married under the law. As to whether there's ever a 'wedding' performed, that would be purely a social/religious ceremony which would confer NO additional 'rights and privileges', in the eyes of the state at least, on the couple involved. In other words, lets separate the church and state a bit more explicitly here, make everyone get a 'marriage' license, but deem 'weddings' as being purely optional, period!
Anyway, that's my option on the subject.

OCU