Why is he treating me like this? did he move on?

Ok! i been with this guy for a 1yr now we go to the same college. right before X-mas o7 when all the students about2 go home 4 the hoilday days he broke up with me he said that we had argue everyday and that he getting stress because of that but he said we will remain bestfriends nothing is going 2 change. we live 4hour aways from each othere whn he got home he hardy talk 2 me and when he did he act like he did want 2 talk 2 me. when we came back after the hoilday he hardy talk 2 me he act like im a stranger like he never saw me before. we had a great relationship,every relation ship have there up and downs. but the thing is we hardy argue every day it was like once a blue moon.What i dont get is why he treat me the way he do. I never chat on him i never mis teat him all way gave him the up most RESPECT! so why do he act like this to me? do u think there so one else? what do you think?