mm1352000:ajobbins: You speak like the meaning of the word marriage has not changed over time (Or indeed between religious, cultures etc). Not all that long ago marriage meant a woman assigning all her property rights to her new husband. And that is just one example of how marriage has changed and evolved in very recent times.
Things change. Meanings change. And you can adapt, or you can be left behind.
I acknowledge it has changed in legal terms... [putting on a Christian hat for a moment]... but from a Christian perspective marriage is a concept created and defined by God that has not changed. It goes right back to Genesis and the creation story; Adam and Eve and all that (did I see anybody wince?!? ).
For a Christian, the idea that humans can define or change the meaning of something that God has instituted is somewhat ludicrous, or possibly tantamount to a rebellion against God.
Once again I say it is unfortunate that the term "marriage" encompasses multiple concepts, meanings and connotations.
Personally I wouldn't have a problem with the idea of putting aside the legal concept of marriage and exchanging it for a concept of formal/recognised relationship that confers some of the practical legal privileges associated with marriage. And that could be a "polygamous" relationship to suit the Masha Gessen situation mentioned earlier.
Actually, polygamous marriage is part of your biblical definition - check how many wives Solomon had...
Also, the bible has four times as many references to thou shalt not eat shrimp as is does to thou shalt not be gay. Picking and choosing from everything the bible does and does not say is a time-honoured tradition.