Thanks for your replies and advice. I agree I shouldn't probably meet him (reason for my username) but I've decided to do it anyway.
To answer the various questions:
why am I going? Because I was so in love with him, have thought about him a lot during that time, was seriously infatuated and have never met anyone else I liked that much - probably because of him. At the time we split up, we had been talking about living together. I figured that if I meet him and don't feel anything that would be great. If I don't meet him, I'll always wonder "what if" and given that I still haven't met anyone else, I can't see I have much to lose really.
how? He sent me an email saying how long it had had been and suggesting some dates for dinner. Initally I was all "no way, I never even had an apology" but he persuaded me round. I'm pretty sure he is angling for shag but I'm definitely not going to sleep with him. Could be open to a snog though. 
I think "smile and act indifferent" is the good advice. I would like an apology but I think I know that the reason he didn't before is that he didn't care so it probably would be stupid to try to get one.
I would like to try to communicate to him that if it goes ok, I don't want to see him again if he ever behaves like that again. It ended up with me being sort of "silent treatment" on him - in the years/months we haven't been in contact, he's tried a few times but I've just ignored it and he gave up. He was horrible, we had a row and then I never spoke to him again until now.
I don't know if it's really dopey to even think it's worth trying to convey to him "I didn't speak to you for years because of this, I hope you've got the message that I won't put up with that." I'm probably over thinking anyway as he probably just wants a shag.