I can't stand the way I've been treated. How do I get him back?

I know it's stupid to try to get revenge. I just hate the way I was treated and I hate the way he will probably treat other girls. He never was with anyone before he met me. I didn't want to even be with anyone before I met him. I was tired from previous relationships. But time went on and we "fell in love". Everything was great since september. I really thought he was for real. He even proposed to me on one knee with a ring and everything. We had our problems and one night we got into it because he wasn't listening to me at one point and was busy looking at his phone to see how long we were on the phone! I wasn't talking about the relationship or anything. I was venting about other things. I went off and accused him of not loving me because of repeated stupid behavior. I even accused him of using me for . That night he texted me goodnight. That morning; texts me good morning. Then when I try to call him that afternoon no answer. No answer for 3 days straight. I lost it! Broke up with him on his voicemail. Felt bad about it, but couldn't take it back. I went to his house and he told me everything I accused him of was true. There were a number of things, but using me for was one of them. WTF? After all this time and it's all just physical. WTF? WTF? So we've been split up 3-4 weeks now. What's messed up even more is that I worked for him so I had no way to pay my rent. If I wouldn't have started my new job last week I wouldn't have had anywhere to live. I would've been staying in the car. He didn't even care about it. He just ditched me. I swear I didn't do anything to deserve that. So anyway, he hasn't even changed his pwords knowing I know them. So I have access to his facebook and e-mail. He's obviously looking for another girl based on what I've seen. But I won't look anymore. BTW he was obese when we got together and now he's on his way to being on his tile. Maybe he grew an ego. I'm not sure. It's just so confusing! He was my best friend. The greatest guy I had ever been with until he screwed me over. Please tell me what should I do? If you really wanted to get someone back who did this to you, what would you do? Is there a way to do it without being completely ridiculous? I need a very intelligent and strategic response. I don't want to hurt him so much as just make him realize that you can't mess with people like he did to me.