That's it exactly, T-Bone. Having worked as a matrimonial lawyer for some years (not my fave bit of law) - I have to say that the no.1 reason for marriage breakdown is lack of communication between the parties. Not being able to say how you feel/think/want about something (whether nice or a potential difficulty) and/or not listening when your spouse tries to talk to you. Parties need to say honestly what they want to say and not leave it to the other person to guess/mind read/know by intuition or revelation; and the listener needs to listen and hear what's said, not just the words used.
On "The Marriage Course" I think it's said that if you have a row with your spouse, do it holding hands. Reminds you that you are tied together and you need to pay attention to the other party.