@shauna14,
Be with him if you feel like being treated like a second thought.
By now you should have seen a pattern to his behaviour. You already know it, but you want the highs that go with 'when things are good'. But those moments of 'when things are good' are only veneer...a put on by him to get you in bed. Have you noticed it's all his way? Have you noticed yourself behaving like a Yo Yo, and he's the hand holding the string?
He doesn't have any respect for you...and you're not displaying any respect for yourself (and why should he display respect for you if you won't do so for yourself?)
You can stay pining for him, and make yourself miserable. You can stay pining for him and let him treat you like crap. You can stay pining for him and let him confuse you all ends up. Don't let anyone tell you that you can't let him do that to you.
The approach that gives you self esteem, that gives you self-respect, that gives you those two things that are the foundation of true happiness - you can put that on hold for years down the track, because really, at your age, it's too damned tough to do anything else.