What do I do to get my love back or is it over?

We’ve been dating on and off for 3 and a half years but never been “in a relationship” though sometimes act like it. We went to the same hs and now the same university, work together and even share a lot of the same friends (some who dont even know about ‘us’). Since we’re not together our agreement was we could date other people but no sex and we must know about who else we both were talkin to. For the past 3 months things between us have been the best they’ve ever been.

Until recently, he used a coworker’s phone to get onto fb and I read his inbox. In there I found messages from different females. One of who I approached in hs because of him (and now attends my college) stating that concerns about him not wanting to b seen in public around her. I even realized this but it eased my feeling because it reassured me he was done with her. This message proved differently and bothered me. I also saw that he was trying to talk to random fb girls.

These messages were about 1 month and a half old but bothered me. I confronted him and he flipped on me! Saying he was tired of us always arguing and that I should trust that he wasnt messing with any other girl. (My jealousy has always been a problem all these years.)

After arguing for 2 hrs he says that he’s done and I should pick up ALL my things. I went to talk to him in person a couple nights later and he said, That us getting back “breaking up” and getting together is done. I doesn’t care about me or us anymore (after almost 4 years.) I love him to death and I know I messed up, but what do I do. I really want him back. Do you think I should let it go and that he’s really done? This happen 4 nights ago and I can’t stop thinking about him and help feeling depressed. Help!