Seems as if we have the exact same problem. I don't stutter near family or friends. If I feel as if I'm going to I just slow down or simply overcome the battle in my mind. It's when I'm talking to strangers that I get tense and can't overcome the battle in my mind, usually on vowels. I think majority of people have this sort of stutter. I'm a heavy believer that this is all experience & confidence related. Once you're more confident and had experience talking to stranger you'll improve as I have drastically.