Very competitive friend

I have this friend and everytime when we go out its like a competition. Everytime we go out and meet somebody she always trys to make me look bad. And whenever I meet somebody I like I have this felling she's going to try to have sex wit them what do I do?

She doesn't seem like much of a friend to me. Lose her. I know it sounds harsh, but seriously, in the looong run, you'll be better off. You should NEVER surround yourself with people whom you feel disrespect you, or with whom you cannot trust.