I have to say in all honesty I would go to dinner and enjoy it. You can show him how awesome you are and what he's missing. But have no expectations whatsoever.
My H has totally and completely moved on. If he showed me a tiny sign that he wanted to meet with me sometime for dinner and a chat I would jump at the chance.
Good luck!
Me - 44 Husband - 47 D20, S18 BD - Aug 2013 Moved out - Jan 2014 OW discovered Jan 2014