Hi there Briar,
I agree with the other men here who advised a cooling off period... even if for no other reason than this: should you decide you want to be friends with this guy when all is said and done, a little "no-contact" time gives you a chance to get to a spot emotionally where you can come back to that person in the true spirit of friendship rather than that of the heartbroken lover hoping for something vestigal to hold on to.
A few years ago, I had my heart broken really badly by someone I was seeing. It wasn't a big, dramatic breakup, but it really took me by surprise and hurt a lot. I still tried to be his friend thereafter, but when he showed up (invited) with his new boyfriend to a birthday party that my friends were throwing me, I thought I was going to die of heartache right on the spot! (Yes, chungo44, it happened to me too!) Well anyway, that was when I knew I needed my space, and I figured I should say something so that it didn't just come across as me rapidly turning into an asshole overnight. I remember telling him that I that I really wanted to be his friend, but it was too hard to do it right now, so could we please just give each other some distance for a while. He said he understood, and was glad that I spoke honestly with him about that.
Strangely enough, just us saying that to each other made the next few months of recooping and regrouping a lot easier because we both knew where we stood and somehow "understood" that there was a boundary that needed to be respected by both of us for a short time. And sure enough, when we finally saw each other again and talked for a while after a few months, we were able to be friends. And although I can't speak for him, I believe the reason that was possible was not only because I wasn't in the same spot emotionally as I was shortly after the breakup, but also because in that "no-contact" time I had come to peace with that "history" that gregstevenstx was talking about and was able to asses for myself what I was really hoping to get from/give to a friendship with that guy. I think that until two things happened, it was sure to be damn-near impossible to be his friend.
I don't know if my story helps you at all and I apologize for being a bit "long-winded", but I guess it's just a little experience/strength/hope from a guy who's been there to pass on to you. Keep your chin up.... one way or the other, you're gonna be okay.