How do I fix this, I screwed this up so bad it isnt even funny?

I was a complete snot to my boyfriend. I was insensitive, mean and rude. I don't blame him for deciding it was over after what I did. I was talking to him in a calm voice, no crying no nothing, trying to work it out. He said he doesn't feel the same way anymore, which he shouldn't. We talked, and we decided to end it. He went silent, something he never does because for as long as I've known him, he always runs his mouth. I asked him what was wrong, and he said I don't know, I've never felt this way. I asked him what he was feeling and then he said its a mix of sadness, greif and regret. Then he started crying. How do I fix this, I cant stand it, and it's all my fault. I asked him what was on his mind and he said how much I know I'm going to regret this. He basically went from lets just be friends to I'm going to regret this. If he said he just wanted to be friends, why did he cry about this and say all those things?