Anyone else not stutter at all when speaking alone?

Anyone else not stutter at all when speaking alone? I just don't get it. If I'm talking alone, I don't stutter at all. When I'm facing someone, it's like my entire vocal cords tense up and I stutter like a madman. As frustrating as this is, it also gives me hope because i KNOW i can talk normally, I just have to figure out why I tense up so bad...It's like it's a bad habit at this point.