Should I leave him hanging?

I think you should let him go, nobody deserves to be treated negatively, whether it be a boyfriend, friend or family member. You should respect yourself enough to realize who is having a negative impact on your life and work to correct it.

If he can't treat you right, then you deserve better. 6 years of knowing him and he's mean to you? Is he intentionally mean and hurts your feelings? Does he know that you have feelings for him?

Just take him out of your life for good.Let him contact you, live your life without him unless he makes the first move. You can sit him down and talk about your feelings, it's the only way to understand his. Plus you can ask him face to face if he really does like another girl.