This is yet another instance where government intrusion in to marriage works to the detriment of the institution. By hanging all of these other civil legal matters on marriage, the government is complicating the issue and giving some people a powerful financial incentive to divorce. A few of these may divorce civilly, but remain married in their own eyes, but how many of these wind up divorcing completely and dissolving their bonds?
The solution, of course, is to get government out of the marriage business altogether. Let people get civil unions for the purposes of benefits, property, and taxation. Then if they choose to get married by some social or religious institution, or all by themselves, that is their business, and the government would have nothing to do with it.
The gay marriage issue is squabbling over government benefits, government encouraged private benefits.