What do I do about my crumbling relationship?

You have given this relationship a lot of chances. It's time to throw in the towel. It's not a good idea to be with someone you keep hoping will change or get better. You need to accept that this is who he is, and if he's not treating you the way you'd like to be treated, you owe it to yourself to move on.

It's always hard to leave your first, but it sounds like you will both be better for it.

Yeah, It's time to tap out. You've broken up 3 times before? Remember that if a couple breaks up once, then that issue that broke them up is -still- there, that's the reason why you break up in the first place. Memories bring you back, but the issue will -still- break you back up again. If you're not compatible with a person, you're not compatible. You sound like a wonderful woman. A guy that takes that for granted doesn't even deserve half as many chances as you've given him. Another thing is: Communication. When a couple is having an issue, this is the most important factor. If you can't talk to him about how you feel and you feel that you're not getting the emotional support that you deserve, why stay with this guy? Yes he was the first everything, but if things aren't working out, it's time to jump ship. If you don't feel like playing this eternal game of cat and mouse with this guy, it's time to push the big red button on this relationship. People don't mature overnight, you know? The best thing for a problem like this is distance. Don't answer his calls, don't be around him, keep your heart away from him. It'll be hard, but think about it. How many times has he done it already? Don't keep putting yourself through this misery. Situations change, yours is one of them. There may be a guy out there literally dying to get a girl like you. Don't you think he deserves a chance? Won't you agree that you deserve someone who will treat you like you -should- be treated? This guy has gotten -way- too many chances and it doesn't seem as though he'll be trying to change anytime soon either, not talking to you and all. You're done with him. If you two don't break it off, he'll never learn what he does wrong anyways because you keep going back to him. Third time's a charm they say. The Fourth time? Well, that's up to you.

Listen babe, a relationship takes two. Both you AND your partner. It's gotta be someone that is willing to return the love you give them. You're right, the relationship is half assed, and it's only gonna hurt you more if you try to keep it up. I know you love the guy, and I understand the situation, but you gotta make a decision. Lay out the problem and try to work it out and reconcile, but if that doesn't work then you've gotta try to move on. Even if he is just a little immature, he should still understand what you are trying to say and what you feel. Don't stay where you are not wanted and treated like you deserve. No guy is worth all that pain. And yeah, Nightshadow would know something about this. Listen to her.
The lyrics of the song below might help a little. Good luck.
"Almost Lover" - A Fine Frenzy

Well, this situation has many similarities to the one I'm in at the moment. If he doesn't call and you two don't communicate, then I don't think he loves you. However, things like memories could be what keep bringing him back to the relationship. If you've given it three tries and each time it seems like you are growing more distant, then I think it's time to move on. If you two are supposed to be together, then it will happen eventually, but for now you should try seeing other people.