hiya-
gee, let's see. you start getting on with your life and now here he is, trying to suck you back in. an apology and lunch?
you always have the option of saying "no thanks, i'm busy." in my opinion, that would be the wise option.
however, if you do go, take what he says with a grain of salt. talk is cheap. we like to imagine them like a big duck, quacking....quacking "i love you. i'm sorry" and then nothing changes. just a bunch of words.
pay attention to what they DO, rather than what they SAY.
don't take the bait. the easiest way to do that is to not see him.
naive