i see, now it's not enough that it started out that way, now you want it to have remained that way, and further qualify it by adding 'western world' into the equation. sorry, don't have time to play move the goalposts anymore, but i will add this:
the premise of the statement i was arguing against stated that (paraphrased) "it shouldn't change because it has always been that way, forever." well, it wasn't always that way; it changed and evolved into something it wasn't originally. who is to say that it should not change again? a bunch of religious yahoos who want to project their morals onto society at large?
the argument "but marraige has always meant this and we shouldn't change it" is also patently false, as has been shown over and over; plus think about this - why is changing the meaning of a word so offensive to some?
whether or not any particular person wants it, ideas and constructs evolve. deal with it - you can't change it. you may as well not waste your energy fighting it, because it's going to happen anyway.