Honestly TC; you need to understand, i am a psychology major and i kinda specialize in what im about to say...
... i can tell by your post that you have only been with your girlfriend for about 2-4 months. You need to know that unless you cheat on her, she will break up with you within 2 years. If you do cheat on her, she will break up with you in about 3-5 years.
If i were you, and i was too insecure to be single for a bit; i'd just keep her around until i find something better, then leave her for that person the same day.
I can clearly tell that you and your current girlfriend are just not meant to be. Im sorry if this is a little off topic.