I've been dating my boyfriend for nearly four months now. We get along well, considering he's one of my only friends. We trust eachother with all of our secrets and because of that, I'll respect his wishes and won't tell a soul what he told me. He's a stereotypical male. Big and tough, a provider and a family man. I realize now that as I'm describing him, he sounds too perfect, but believe me, he has his fair share of quirks and imperfections. Excessive pride being one of them. It's because of that pride, he worries me. I understand men are rarely emotional, and I know they don't like feeling weak. It's one of his biggest fears. I know he hates feeling weak, but when he opens up to me, tells me about his past, the people he used to hang out with, the things he used to do, he loses his tough guy appearance and his iron heart turns to a soft fluffy cotton ball. He has a naturally high body temperature, a heredity birth defect. When he opens up to me, his temperature literally drops back down to normal, and he starts shaking like a Chihuahua. He feels light headed and dizzy. It's happened everytime he told me something very secret and very import and it worries me. Is it normal? I'd prefer answers from guys who understand what he's going through, but any kind of answers I can receive would be much appreciated.

Guys are like walnuts. (Excuse the poor metaphor...) They're all tough and difficult to crack open. But once you do they're either sweet and soft or black and rotten.
If I'm describing something personal, I'll still appear to have my cool on, but I'm noticably shaking and start feeling sick - Pretty sure it's anxiety.
You should be happy that your husband is able to open up to you, that is not easy. And you should be supportive when this happens. Even the hardest people need support from time to time. Sounds normal to me.