I'm sorry you're having a tough time. For some reason when I was in school the guys my age were totally not interested but guys 5-10 years older were. Sounds ok on the surface but my parents weren't thrilled and somebody 5-10 years older doesn't want to go to a football game, dance or prom or hang with your friends. Very disheartening. Is it possible that you're interested in guys that aren't 'available' or in the case of you being cheated on....jerks?
Keep trying. I don't know why this is happening to you but you'll find someone worthy of you. Best wishes.