Without knowing any specifics about your relationship, it's hard to give accurate advice. Obviously, stuff like communication and honesty are staples of a healthy union. But if I had to pick one non-specific thing that would help marriages the world-over, it'd be this:
Work the knob.
Seems to me that a lot of marriages break down because someone is being too cerebral about something they should chill the fuck out about. Communication and honesty should be a constant, but if things get quiet, couples can always stay connected by working the knob.
Especially, as this question is from a woman (or a gay man), working the knob deals with many of your man's manly type issues. If he's not talking, it's probably not because he hates you. Most likely it's that he's stressed out. A good knob working does wonders for stress.
Good relationships are open, caring and full of knobs getting fucking worked. People start to lose sight of how important it is to get into each other's funny bits. When you stop that, you're risking the intimacy of your relationship. Of course you don't want to be married to someone you're not doing it with; you're turning your lover into a roommate, or worse, your brother.
When things seem down, and one of you isn't in the mood to talk, try fuckery. It'll keep the bond there until the time for talking arrives. And you'd be surprised how often a good polishing can get the words flowing.
Short Answer: I think this is also why so many people end up being unfaithful in failed marriages. They're not getting their intimacy, so they look for it externally, in the most immediate and shallow way. It's still inexcusable, but I think most people would generally prefer the cow at home, as long as the doors to the yard are open...metaphor failing...abort...