WHY is this so difficult?!

Okay...so this guy and I have been seeing each other off and on for 4 years. We finally came to the understanding that we love each other, we are absolutely soulmates, and there is nobody else out there for either of us. He was the first to tell me he loves me, the first to say he wanted to spend his life with me, and the first to say that if we weren't together, he wouldn't ever try to date anyone else. Because he knows that it's pointless because he'll never love someone as much as he loves me and blah blah blah.
Not too long ago we were broken up and he was asking for me back. For the first time ever, I didn't say yes right away...I told him I needed to think. He went all out...he told me how he knows he was stupid in the past, but he's never going to let anything come between us again, and he's ready to finally settle down and spend the rest of his life with me. He said he realized single life didn't compare to having me there when we love each other so much.
Here's where things get shitty...he just broke up with me a few days ago. He didn't even give me a reason...the closest he came was saying that yes, he believes I'm the only one for him. No, he's not going to date again. Yes, he loves me very much. But no...he doesn't want to be with me. He tried to push me away and has been so mean. Now our friends are saying they don't think he'll come back because they don't think he wants to date, period.
This just doesn't make any sense to me...I know it's because I'm extremely close to the situation and I'm just not thinking clearly. Can somebody please offer some kind of insight or advice...anything?? I'm so hurt right now...

just a little extra information:

we were actually doing really well at the time of the breakup. we were getting things on track and things were going in the right direction...we seemed happier than we have been in a long time.

also, i know this sounds like he's just feeding me bullshit...i don't believe that, though. so please don't try to use that excuse...i've had so many people tell me how much he cares about me. even in our hard times, he's very loving. this is not an issue of love. i am firmly confident in that. this is an issue with him and his noncommittal ways. what i don't understand is why he wanted be back so badly so we could finally settle down...and then did this. that's what i'm mostly confused about.

Girl, Im going thru a similar thing and was even asked to marry 2 months ago, now he broke us again so I will be reading the answers you get. Theres nothing we can do but take care of what we can for ourselves, not having to do with the boys. Do NOT contact him, in any way. Somone said on here in another thread that men dont like to see their investments back on the market. Its sick to think of a relationship as a business but after all these years I am afraid I see the connection. Live your life fully as you can. He may never be able to steady himself. Though he may come around. But your best bet is to be in top shape weather he comes around or not. My fiance broke us up a week ago and it made very little sense because it was the first I had heard of his thoughts and he was pointing fingers at me for things that HE was doing and more of, things to get in the way of our goals. So I guess it was all my fault suddenly and w/o a sit down and chat he just snaps his fingers and its over. So I have found that so many people dont give the true reason for break ups when they do the breaking. I think with your boy and my ex there is something inside of them they still have running loose, like the child they havent grown out of?