Originally Posted by
ttylox
Well, you're 17 so the likelihood of you having a "veerrrry" long anything is pretty slim. But for sake of argument, yes your behavior is "dangerous" and it seems you must know this or you wouldn't be here seeking advice. I suggest you keep this possessiveness crap in check and realize that if you continue this behavior you'll never be in a healthy relationship... the best you could hope for is co-dependence (which, actually sounds like exactly what you're looking for).
If your girlfriend really likes you, she'll be faithful to you whether she talks to other guys or not. So chill the hell out. Otherwise, you're going to suffocate her and the only thing that can come of that is resentment.