Dear 100 Hour Bored,
If you and a member of the opposite gender were stranded on a desert island with no chance of ever being rescued, would it be ok to...well, repopulate the island? Because it's obviously ok for married couples to have kids, even if they weren't married in the temple, and if you two were the only ones on the island, then you can't really avoid sharing the rest of your lives together and committing to helping each other and stuff, which is a lot like what a non-temple marriage is anyway, right?
- Mary Ann
Believe it or not, this one's already been answered.
I take issue with your characterization of non-temple marriages as just happening to live together and help each other out. A civil marriage may not be an ordinance from the Mormon perspective, but it's still an important social contract that's significantly different from being stranded on a desert island.