Your question reminds me of the twelve-year-old boy who had never spoken a word. His parents and siblings thought he couldn't talk because they'd never heard his voice. Then one day the boy's mother placed some soup in front of him, and he ate a spoonful. Then he pushed the bowl away and said, "This is slop, and I won't eat any more of it!"
The family was ecstatic. He'd actually spoken a complete sentence. They all jumped around gleefully, and his father said, "Why haven't you ever talked to us before?"
The boy replied, "Because up until now everything has been OK." Maybe your boyfriend will surprise you one day with a flurry of words, but I doubt it. Shyness and an introverted personality result primarily from an inborn temperament that tends to be very persistent throughout life. Research shows that approximately 15 percent of children are genetically programmed to be somewhat introverted like your friend and that most of them will always be that way.(128) It appears that some people just seem to be born "noisy," and others prefer to keep their thoughts to themselves. Your boyfriend may be one of the latter.
If you choose to marry him, I hope you'll do so with your eyes wide open. You're probably not going to change him. Many women fall in love with the strong, silent type and then resent their men for the rest of their lives because they won't talk to them. It is a very common source of frustration among women. But that's the way it is.