He has organised for us to get together once before, and it ended very badly! ... now he says its different, argh.
Ah ok, I dunno Kitten! You would know him better than all of us on this forum. If he messed you about before, that makes it a whole lot different, but call me stupid, I like to believe in people, and maybe this time round he means it, maybe it is different. I still think you should rather take the chance and hear him out. Make it clear when you get there that you're only there because he said it was different and if it's not you are gone and he shouldn't bother contacting you ever again. You should be able to figure out whether he's serious or not rather quickly and whether this time is any different than the previous. From here you can at least then act accordingly.