BTT

It is those who push for change who must open the box to describe and give practical examples of what marriage will be. What it is and they are so dissatisfied with, is understood and has stood the test of time, but exactly what is the replacement/s that will 'evolve' and how does it/they work?

Ooo... I wanna have a go at this one.

<<It is those who push for change who must open the box to describe and give practical examples of what marriage will be.>>

The same as what it is now, only between two consenting adults instead of a man and a woman specifically.

<<What it is and they are so dissatisfied with, is understood and has stood the test of time, but exactly what is the replacement/s that will 'evolve' and how does it/they work?>>

Nothing needs to be abolished or replaced. You're being melodramatic.

[Damn, now I've got that annoying Chris Rea song stuck in my head again.]

//It is those who push for change who must open the box to describe and give practical examples of what marriage will be.//

I can give you a description, but I'm single and marriage is really not on the cards ATM so I can't furnish you with practical examples.

The description:
So you know how sometimes blokes and sheilas really hit it off together and sometimes decide they want to stay together for the term of their natural lives, or until they get thoroughly sick of each other and petition for divorce? Well, it'll be just like that, except that we'll let two blokes and two sheilas do it as well.

//how does it/they work?//

Same way as it did between a bloke and sheila, mate.