I share your Godly values. I need to start with that because I really believe that you and I are coming from the same place.
You need to cancel the dinner. This isn't about game playing. This is about getting the upper hand and really getting an understanding of your situation before you walk into a mine field. If you go to that dinner then you really were sitting home waiting for him. That's the impression you give because you accepted the first invitation. And maybe cancel is the wrong word... reschedule is a better word. Make it for another day.
I know you want to get "it over with." But that's an illusion. You go to this dinner and he tells you he wants a divorce. Next week, he may not. He goes to this dinner and tells you that he wants you back, if that's true you'll find out at the rescheduled meeting. But sweetie, you need some control here. And you do not need to lie and I do not agree with lying. You simply tell him that Thursday does not work for you after all and that you need to reschedule. That's it.
I, too, am very interested in what the coach has to say.