Moving in with your spouse only once you've tied the knot is asking for disappointment and inviting unnecessary stress on what should be a time for two people to seal a permanent bond with each other. It seems irresponsible and almost naive for couples to expect that their vows will be strong enough to see them through the rough spots, especially if you have to experience them all at once. Before living together, we're really only seeing two dimensions of our partner's personality – the third dimension might just prove to be more than one can handle.