Society today is very different to a time when marriage was for life and the idea of a couple 'living in sin' was... well... frowned upon to say the least. Here are the statistics for today.
Statistically in a group of 10 people :
Two to three will have had either 2 or 3 defacto type relationships.
One or two will have had 3 or more.
FIVE will be heading for there first split!
So with this in mind it could be a very costly exercise to have the potential of 3 or more costly settlements. However if you and your (ex) partner can decide amicably then it doesn't need to be drawn out and expensive.