Hi Maddie...
Wow, not sure if I have any advice on this. I know it must be hard.
I spent a lot of time trying to figure out how to "send the best message"... that really hit home with me. These days, I consider that kind of thinking just another long way around to the point of trying to control someone. Hitting him with a baseball bat may not be the right answer... or legal... but other than that, lately I am of the opinion that true "reactions" are ones that come naturally, and that premediated attempts to "send the best message" are really nothing more than attempts to manipulate another person.
I remember I used to hate it when people would respond to my cries for help with "Have you been to Alanon or Naranon?" but... um... have you? I promise, promise, promise it helps.
Maybe it won't help tonight (which is what I wanted to scream to the computer screen, like, "Oh yeah, like that's going to help me now, ladies!") but the truth is, tonight is probably not the end all be all of your relationship. It feels like it, but it's just one more day in a string of a lot of days where maybe you haven't been too satisfied. I always thought there was that one thing, that one day... that one word that would matter. And there just isn't. It is really just all about the drama when you try to make one moment into "the moment"... we don't live in a Lifetime movie, although I often wished I did (except, of course, for the true crime dramas, when someone doesn't end up so well!).
I don't know. Tonight is probably not going to go too well no matter what you do. In a time of crisis, I find the best method is no reaction until I have time to ponder my thoughts myself, but that might not work for you. If you haven't been to an Alanon meeting, at least try it, IMO. It can't hurt, and it gives you some personal tools to deal with just this type of situation.