Frosty: yes, that is interesting. I'd heard that before. Do you know whether such studies have incorporated cohabiting couples? I wonder whether the problem may be in part that single men generally find isolation harder to deal with - it's a common observation that women are better at keeping up their social networks. And as for the problems facing married women, I presume that's related to the inequality in the way male/ female partnerships still operate . So it would also be interesting to compare male and female gay couples with hetero marrieds and cohabitees, though it's possible that some of them may take on 'dominant/ less dominant' roles as well, leading to higher rates if depression among the less dominant partners.
Fothering - ah, yes, that makes sense.
Marantha, some people were saying marriage is nothing more than a legal contract. I compared this with saying that having children is nothing more than genetic procreation. You can, of course, have children without having any involvement in their lives post-shag. You can also get married without showing any commitment to your partner post-wedding bells. But we don't usually define concepts by examples of where they operate at their worst, do we? Hence why it was necessary to counter the reductionist arguments with a positive statement about what good marriage is. Also it should be noted that I am talking about being married, not just getting married, whereas the 'piece of paper' arguments appear to only relate to 'getting married' bit.
There are plenty of excellent reasons for co-habiting, not least of which that it offers freedom of choice for people who want to consider a range of commitment options which may or may not include marriage.
I've found it interesting to observe on many occasions that former cohabitees have said that being married changes the way they feel about their relationship (for good or ill). And of course, the statistics showing different separation rates among marrieds/ cohabitees support the idea that getting married changes something about the way the couple approach their relationship . So the decision to get married, the beliefs one has about marriage, the community aspect of the marriage commitment (the Quakers make this bit particularly significant), the legal element, the way one behaves in a marriage - all of these factors are what make a marriage whatever it is. In other words reducing the concept of marriage to just a piece of paper is inadequate.
And btw, nowhere have I said or implied that cohabiting couples cannot have a commitment to each other. Anyone who thinks that's what I'm saying is adding their own assumptions to my words.