Next time you're in a relationship, don't passive-aggressively wait for the other person to slip up as an excuse to get out of it. If you're unhappy, then man up and actively break up. The vast majority of relationships end, and high school relationships nearly always do. You're not a bad person if you end it if it's not working out. In fact, that is a good and mature thing to do.
And like the fellows said, live your life and don't spend it hanging around and waiting for this girl you have a crush on (it's a crush; please call these things what they are).
Don't live your life passively waiting for things to happen. Get out there and make your own destiny.