Why is he acting like this?

I had the same problem with my boyfriend. we used to be so close, and yes, we would have our fair share of arguments like every other couple, but we would never be able to stay mad at each other for too long. but like one day, I had had a rough day so I wasnt in the best of moods, and I just snapped at him - he was trying to wind me up and it was succeeding. this was while he was walking me home, and after I snapped at him he just didnt say a word the whole way, only walked to the end of my road as well, when he usually walks me to my house. then we didnt speak properly for days, didnt accept any of my apologies.. im not stupid, I knew he was going to dump me but he didnt have the balls to say it, so one day I just asked him if he was going to finish it, and all I got was a simple yes. no reasons, no explainations, nothing. I dont understand. we were together for ages, and the week or so before he had cried because he thought I was going to dump him. thats whaat makes it even more confusing. just try and talk to him about it, if it comes to an end then you will just have to think positively - smile bcos it happened instead of crying because its over :)