Rosey - when I read that you still see him, I thought "Aha.... there's your reason."
You have to go on a HE-tox, my dear to get him out of your system. No contact. That means not seeing him, talking to him or even listening to his voice on your voicemail.
Why don't you try it for 30 days? If you can stick to 30 days of NC you will be amazed how much better you feel. It might even spur you on to go NC for longer.
He isn't giving you any commitment or meeting your needs, yet he is conveniently keeping you roped in by throwing some tantalising scraps of time and attention your way. Sorry to say it, but it suits him to have you on the backburner.
Why would you want to put yourself through this indefinitely? Better an agonising end than endless agony.
Years ago I had a ex I couldn't forget. That's because we were still in touch sporadically - it is like picking at a scab - the wound never heals properly. I finally realised this and cut him off completely and it's the best thing I ever did.
With the benefit of distance and silence, I see him in MUCH less romantic terms.
It's all about disassociating yourself and the process of detachment takes time. When you start to detach from him physically - not seeing him, cutting contact (including not texting him) - your emotions will start to follow.
Trust me, I've been through this process of detachment loads of times 
I'm not saying you should become his enemy overnight, but you can't be friends with someone you still have strong feelings for. That's not to say you can't be friends again in time but right now you need a clean break so you can get the healing process under way.