Marriage and divorce statistics from the ABS concentrate on what many might describe as traditional or conventional relationships.

However, increasing proportions of the population of course have a range of personal relationships that may have nothing to do with marriage.

And the nature of these relationships can have wide repercussions on a couple's finances including possibly the splitting of superannuation if their relationships break up.

For instance, the latest issue of the Family Matters journal, published this month by the Australian Institute of Family Studies, looks at adults who identify themselves as being in a relationship yet live separately.

The journal quoted statistics gathered by the Melbourne Institute for its Household, Income and Labour Dynamics in Australia survey showing that 24 per cent of adults are in such relationships.

The feature in Family Matters has triggered discussions about whether the super of such couples could be split following the break up of their relationships. (See http://www.theage.com.au/lifestyle/lifematters/togetherapart-lifestyle-choice-that-may-have-a-catch-20110418- 1dlp3.html)

ABS data shows that 77 per cent of people who married in 2009 (the latest statistic available) had lived together before marriage. And the most recent Australian Census records that the number of people living together in de facto relationships rose between 2001 and 2006 by 25 per cent to 1.2 million.

Since last year, the super savings of de facto couples in all states except Western Australia can be split following the ending of their relationships.

Without question, a couple's relationship can be at the core of many personal finance issues.

* Written by Robin Bowerman, Head of Retail at Vanguard Investments Australia. To receive this column by email each week, register with Smart InvestingTM.