Governments are on a slow path to recognizing alternate forms of marriage from the 'classic' definition. Obviously gay marriage is the big one today but there are other small steps being made; in BC common law marriage is being upgraded to being exactly the same as official marriage. The biggest difference is the 50/50 split of assets accrued during the common law marriage but spousal support and pension benefits are pretty important too.
I have seen some people complaining about this law as being good for con men/women who can get into a relationship and then demand half of their partner's stuff down the road but I think that sort of objection is utterly ridiculous. For starters a confidence game that lasts a number of years and which is worth nothing if detected 18 months in seems like an unlikely proposition. Not only that but this only matters if you can't get the mark to marry you; if you can manage to live with them for years at a time is it really so unlikely that you can't get a ring on your finger?
Really this is just a good step to protect people who have children in a common law relationship, particularly if one of them ceases working to raise the children. After a breakup it is going to be difficult enough raising children alone without the added burden of a career that is broken or nonexistent and having no support. While I went about getting married officially I don't think that there is any particular reason to enforce that. If people want to get married, great, but we should strive to arrange things so that the people in a position of power (those with good careers in common law relationships) cannot abuse their position and leave their former partner out in the cold. There is no need for an official marriage to be required to protect the vulnerable.
This got me thinking about polyamorous relationships and how complex marriage law can be when you consider them in the mix. It is a little complex but certainly not impossible to imagine a cohesive set of laws for 3+ people marrying each other all at once but situations where 1 person is involved in several separate marriages are potentially insanely complicated to work out (graph theory applications!) and adding common law recognition into the mix is nutty. If you have a married couple with a roommate who they sleep with, is the roommate part of their marriage as common law 2 years in? Complicated!
While I would love for polyamorous marriages to be part of the law every time I sit down to figure out exactly how it would work I end up with a bunch of impossible problems and no answers. I guess my hacked together solutions might be better than the current nothing, but making laws on the premise of 'well, this probably isn't worse than what we have...' isn't a great starting point. If anyone knows of somebody who has worked this out in a coherent fashion I would love to read about it.