You mentioned that you were afraid that if you tell him you want to do couples therapy that this might lead to early divorce before you have your ducks in a row.

Then you mentioned he said that if it comes to couples therapy that in his eyes, it's already over.

I think his attitude shows that he is afraid to face his issues. This is his way of trying to scare you out of couples therapy.

If you bring it up and he gets upset, you still don't have to mention divorce. Then you can say at least you tried your best. If you expect him to get upset you can mentally prepare yourself for it. You can remind yourself that he's not really mad at you, he's just lashing out because he's afraid of confronting his problems. Plus it's more affirmation that you are a good person trying your best. You deserve respect.