Telling ADHD spouse to leave...

He's fighting me tooth and nail. From begging to attacking to generally being obtuse. I've tried explaining several different ways about why he needs to move out. I can no longer take the financial hits, the passive-aggressive attacks, the piles of dirty laundry, cleaning up after his plethora of pets, the trash left everywhere but in the trash can... after six years, I just can't anymore... I've told him if he gets his own place, keeps up with it all, lives within his means, and starts counseling (and between him and his doctor, if medication is recommended, he should), that I'd be willing to consider dating him again and go from there, but he keeps pushing and pushing saying he doesn't understand... how do I explain this to the ADHD brain???