"I'm sure he understood what I meant."
"I'm sure it was obvious to her how I felt."
"It goes without saying..."
The most common source of miscommunication in any relationship is a very simple one: people routinely fail to realize how little they are actually communicating. In other words, we think we've said a lot more than we actually have.
Psychologists call this the signal amplification bias (because we can't resist slapping esoteric names on things; calling it the "I'm sure it was obvious" effect would be much more to the point).
The vast majority of us tend to believe that our behavior is much more expressive than it actually is, and this occurs across a wide variety of situations.
For instance, we often think people know when we're lying -- that our discomfort with deception is obvious -- when they rarely have any idea. We also assume that others understand our goals and what we're trying to accomplish, when in fact they don't have the first clue. Most of what we say and do every day is open to multiple interpretations, and when other people try to figure out what we really mean, they are apt to guess wrong.
We are even more likely to be "sure it was obvious" with people we know well; when it comes to friends, family, and romantic partners, we assume our thoughts and behaviors are particularly transparent, when they are far from it. So, ironically, the risk of miscommunication is greater with your spouse than it is with a stranger.
When we assume that other people know what we're thinking and what we are expecting of them, we do them a real disservice. Assuming that we've been clear about what we wanted, we blame them when things don't go the way we expected, or when we feel our needs are going unmet. Also, assuming that your feelings of love and caring for the important people in your life "go without saying" is a great way to leave them feeling unloved and uncared for.
The next time you catch yourself thinking, "I didn't expressly say that to Bob, but it should be obvious," stop. Nothing is ever obvious unless you made it obvious by spelling it out.
Remove the phrase "It goes without saying" from your mental lexicon, because it is total rubbish. If something is important, then it goes with saying. Make a point of saying exactly what you mean or feel, and asking for exactly what you need, and you will be pleasantly surprised by often you get it.