@Vicky28,
Not necessarily.
But I think you're right to put the brakes on things. You've got doubts and you feel hurt. His assurances didn't seem to be enough, and now he's balked.
You were together for a long time, but also during a developmental phase in most people's lives. That is, you were transitioning from teenagers (never mind your actual years - many people in their early 20s are a lot like teens in their behavior and outlook) to actual adults.
My advice to you. If you don't already have your own apartment, get one. And move in alone, or with a platonic roommate if the rent is too high. I firmly believe that most people really, really need to live on their own, at some point in their lives, even if it's for only a few months. When you're the person who is solely responsible for rent, bills, the emptiness of the laundry basket and the fullness of the refrigerator, it matures you in a way that a lot of other experiences just don't.
And take some time to reassess, and see how you feel. Maybe he has changed his mind and will go charging to this other girl (I hesitate to call her a woman at her age). Maybe he won't. In the meantime, don't hang around. You are under zero obligation to wait (and understand that what is good for the goose is good for the gander - he doesn't have to wait around, either). Experience life, with or without other men. Have fun, sow some wild oats and use condoms if you have sex while sowing said wild oats.
See how you feel, if you miss him, or if someone else tickles your fancy, or if you just want to continue with the single life.