I have been with my husband 13 years (dating, then engaged, then married for the past 9), and I have never seen him cry. Not once.
His ex said the same thing. Except for when their first son was born, she saw 1 tear fall out, and that has been it. When our daughter was born, it was an emergency c-section that I had to be put under anesthesia for and he was out of the room, so I couldn't say what his reaction was when she was born and everything turned out okay.
In general, he can be emotional, but when he is stressed, worried, frustrated, upset, whatever, it tends to come out more as anger, and often a tendency to lash out or find fault with someone else for whatever is causing him to feel the way he feels. I think as a child he was just expected to have to squash his emotions too much, had too many let-downs and disappointments, and now has a tendency to feel more defensive and closed off rather than allow himself to feel more vulnerable and open.