Thanks for introducing a thought-out, non-aggressive opinion into this debate. I understand where you're coming from. I'd have to say that my wife and I too had already formed the majority of the emotional connections that prepared us for marriage before we moved in together.
Of course, my wife suffers from BPD, so our situation was slightly different, as it was partially a test to make sure our bond would survive the instability that comes with BPD.
Oh. Well, yes, your situation is different (but in a way that has nothing to do with the efficacy of cohabitation). I have a cousin with the same condition and she's married to somebody who also has the same condition. Whew! But it seems they're able to keep each other on a pretty even keel.