Zen,

That's a tough one. I'd advise maybe to think about it in a different way, instead of worrying about how you come off to them, maybe just be yourself? If they're true friends, they'll stick by you, and if they're not, they're probably not worth keeping around anyway. If the fact that they talk about you behind your back bothers you, maybe mention it to them? They may not realise that it upsets you..

-Meander