Communication isn't about how much you say but whether each person grasps the other's perspective. If your partner is a reluctant talker, you may be unwittingly fueling his reticence. When he states his case, do you launch a counterattack? Criticize his reasoning? Get upset? If so, he may keep quiet for a reason.
The Most Useful Communication Technique of All Time is deceptively simple, but it works like magic. Next time your partner makes a point, take a moment to digest whatever he is saying. Then say it back to him. Maybe not word for word, but you have to get the gist—and you can't stop trying until your partner agrees you've nailed it. Switch roles and repeat. Once you're not so busy explaining yourself to someone who just doesn't get it, you can look for compromise.
Before I started grad school and officially drank the psychotherapy Kool-Aid, I used to mock this technique as a way to wrap gauze around discord: "I'm hearing that you're a pathetic jerk." "Well, I'm hearing that you're a total loser." But once I tried it, I realized that "I'm hearing..." isn't just psychobabble. It telegraphs the message "I'm listening to you because what you have to tell me is important." And that's the single most important thing couples can say to each other. Mend Your Relationship: Find out how one couples therapist took her own advice and found compromise with her boyfriend