Marriage is in fact already pretty battered. But gay marriage would do it in for good I think.
See, I really don't get this argument at all.
Suppose I marry a nice lass and we settle down together, and have kiddies and spend the rest of our lives together. Why does it make the blindest bit of difference to us who else is getting married, why, and for how long? So Billy and Jim got hitched how does that effect our marriage? So Marty and Sue got divorced how does that effect our marriage?