Advice On What to Say

So, tonight's the night we discuss if we will stay married or divorce. I have been telling him for a long time I am unhappy and exactly what I need from him. I am non-ADHD and my husband has ADHD. I have begged, pleaded, ignored, left him alone, acted normal, acted mad, acted sad...I have tried everything and nothing changes. He has been mad at me for 3 weeks and there is not a reason for it. I told him last night I am going to leave if he is not willing to participate in our marriage. He basically said ok. Then I said, if I leave, it will be for good. I am done with going back and forth. After I said that he said we needed to talk about it. That gives me some hope, but what do I say to him tonight to actually get him to listen? He is not a great communicator so I'm not sure what to say to have an effective conversation. Any tips would be greatly appreciated. Thanks