Should I give up on this guy?

I have been seeing a guy on and off since November of 2011. We hung out and hooked up a bunch for a while, but then we got into an argument because he is terrible at making plans, and I basically got tired of always hearing from him last minute if he was free (and letting him know when I was free last minute). So we stopped talking for about two months. I went on some other dates in the meantime. But then I saw him out one night and we started talking again and eventually started hanging out and hooking up again.

This went on for another two months until I decided that I didn't want such a casual relationship with him. He told me he wanted to keep things casual. We argued, stopped hanging out again. We didn't see each other for about 6 weeks. We had gotten into another argument in the meantime, and I decided to stop talking to him completely. But then he contacted me again, wanted to aplogize for things, and so we decided to start hanging out again. We did not start hooking up again, which was fine by me. However, he did stay over with me a few times, and one night admitted to me that he was dating somone else. I was pretty ticked off that he would be dating some other girl, yet sleeping over with me, and yet again we argued, and stopped talking and hanging out with each other.

Anyway, from the middle of May until the end of June, we did not speak. I had started dating someone else in the meantime too. The problem was, I really wanted to be with my on again off again guy. So I contacted him again. We started talking again, and for reasons that were not related to him at all, the guy I was seeing and I broke up. This was the end of Juy, and then on again off again guy and I started hanging out again.

At first we just hung out, and it was nice. No hooking up. But then we argued again, and about the same old relationship stuff. We quickly made up, and ended up sleeping together again. And for the last month or so, everything has been good. But then this past weekend, he had made plans to hang out with me and ended up standing me up. He got sucked into his fantasy football draft. He has apologized profusely and has told me he will make it up to me.

We have talked about the fact that we both really like each other, we care for each other, we are very attracted to each other, and we keep forgiving each other after these stupid blow-up arguments, and end up coming back to each other. But now that he has stood me up (after he made the plans) I just don't know if I should keep things going. I don't know how long I should wait to see if he really does make it up to me. I have not spoken to him for several days. It's been almost a year and we are still not a "couple". Neither of us sleep with other people. And the only reason either of us started seeing other people was because things were crappy between us.

I don't know what to do. I just need some unbiased input. Where could this reationship possibly be going?