Someone PLEASE explain my ex bf's actions?

I had a summer relationship with this guy. We never got along, nothing in common, he was selfish, I was bossy etc etc. But regardless, we were attached at the hip. We had fun together and everyone knew about us. But when school started a week ago, he got unusually distant.. so I broke up with him. I wasn’t angry, but I told him not to contact me and I wished him luck in life. It felt... finalized. The first night he cried hysterically, tried to talk me out of it, ended up going to my mom for consoling and then early in the wee hours of the next morning, he sent me a lengthy text about how he was so sorry, he still loves me, etc etc. I didn’t text back. I didn’t hear from him for three days. The longest ever. I missed him… So much so that I dropped my pride and called him, saying I’d like to be friends.. At first he was a stunned, but it wore off and he got kinda sarcastic and cold, he said he’d think it over…? He agreed.. But he’s not the same anymore. He won’t contact me unless I contact him and it takes him forever to reply. He doesn’t say much, our convos have gotten so boring. It’s like speaking to a different person. He won’t ask to hang out. If I ask, he says okay.. but acts as if he could care less if it happens or not. But in person, you can barely tell we’ve broken up! He's still bubbly and touchy-feely. But away, he's distant and cold again, sometimes even mean. We’ve both agreed, it’s OVER. But I think we’d make better friends than lovers. Why won’t he cooperate?