<human>: Provide a brief overview of the text.

Hi all,

So two years ago, an ex ended things with me over Facebook, after a week of acting strange, avoiding me, ignoring me. I know I know—should've seen the signs and knew what was coming. I was sad about it for awhile, before I realized that he is a real wimp for not having the courage to do it face to face. A couple days after the breakup, he was really bipolar about his feelings—he wanted to get back together, and then he hated me, and wanted to burn our pictures, and then wanted to become friends. When he saw me in person, he either ignored me or acted like we were best friends and that nothing happened. But he never spoke of the breakup in person, not even when I requested it. 

Basically, we did not end on a good note. Shortly after the breakup, we stopped talking. Now, two years later, I receive a message from him on Facebook. He asked if I hated him and told me that he found his matching keychain that we got back when we were in a relationship. He asked if I still had mine. 

I'm not sure if I should respond, or how I should respond. Is this his way of asking for closure? Does he want to catch up? While I don't "hate" him, I am not particularly fond of him and I still think I deserve an apology for the way he acted towards the end of our relationship. Am I overreacting or being unreasonable? How should I approach this? Should I even respond? 

FYI: He sent the message two weeks ago. I wasn't going to respond but it's been on my mind a lot lately, so I thought maybe I should do something about it.
<bot>: Relationship ended on bad terms, now two years later, the ex messages me on Facebook. Not sure how I should react—is this a way of asking for closure?