He cant be friends with me?!?

my boyfriend n i started out as best friends n ended up going out for bout 10 months. we did love each other but a while ago the spark kinda went away and he told me he wanted to break up w me and just be firends. i was upset but after he xplained that since the spark left we had realy just been freinds hu hooking up once in a while, i agreed with him and we broke up. he told me that even though he didnt love me ne more he still care about me and he wanted us to be friends like wed been b4 we started going out. i saw him at a mutual firends party last ngiht and we did as we used to, we wrestled n we fooled about. but after a while wen ever he would see me, he would give me that buddy buddy punch on the arm, and that was it. he just kept hitting me. after the party i called him and asked y he did that and he said he just didnt kno how to be my fiend. im so confused! whats going though his head? he broke up w me cuz we were just firend and now he doesnt wana b my friend....what do i do?