What does he mean when he says " I see no future with you" REALLY mean? What are the thoughts behind it.?

We've been dating for 5 & 1/2 years. When we first dated, as with all relationships, it was like a dream come true, up until the 2nd year. Things started to get rocky and he told me during an argument he had really planned to marry me when he graduated college but that would never happen, ever. That was 3 years ago, we're still together, we have awesome times together still, we go away on trips and even weekend get-a-ways with just me and him, his best friends love to hang with me as well. A really big problem is that he holds a lot of my past against me, about my ex (when i was younger and was a rebellious one), which i had never done to him. When we are good, everything is just beautiful, but he has a tendency to purposely get me pissed off or upset so I can start the argument, he would NEVER initiate one. I feel like he would also try to make me break it off with him, sometimes he's say " ..when you leave me for someone else..." Whenever we get into an argument ( which he instigates with his immature cowardly behaviors) he would tell me "why do you even talk about it, we're not going any further than where we are now, I dont see a future with you". An example of what he would do would be when I asked him to help drop some boxes off at the UPS store he said ok, then when it comes time to go, he said he had to head home and he'll do it next weekend. I said ok whatever, i dont want to plead with him, he's always wanting people to chase after him or beg him for sh1t. Then he asks me "oh are you sure, i just go now then if you really want me to" Of course i tell him no, I'd rather lug these boxes there by myself then having to beg a man to do something he took his words back on. The thing is he wasn't even in a rush to go home, when he got home he spent 3 hours of doing nothing to get to doing what he "had to go home to do". But the thing is theres so many times hes been very sweet and gentleman like, with money and paying for movies, dinners, etc he is very lenient. But when it comes to showing the care and effort he holds back, i dont care about the money or anything, emotion is what counts. I just feel like the relationship is so empty sometimes, i'm torn because i feel that when we're good, we're really good, when it gets bad it gets ugly. I also don't know what to do because i feel like he has security issues, esp. because there has been a lot going on with his family, i dont want to separate from him, leaving him to think everyone will just leave him, i want to be there for him, but he fights the hand i reach out to him. Also, we've been together since he was 18 and i was 16, we've grown together and feel like we're very much a part of each other everyday. I know the things i described to him to be doing sometimes make him seem like a shrimp of a guy but he really isn't, physically at least. He's VERY masculine looking, tall dark and handsome type, so you'd never figure him to be capable of doing such things. I am 22 and he's 24 this year , I'm at a lost of which direction to take with this...