kech, that is not something you tell him. It is something YOU DO.
How? Well first, you have to deal with him about your D. No way around that.
But short of that, no contact. No discussions, texts, phonecalls, emails, smoke signals, skywriting, etc that have anything to do with anything other than your D and her care. Period.
When he comes to see her, you leave. When you come home you make it clear he is it to leave. If he starts saying things in person, listen and validate. If he texts do not respond. Unless it is a direct question. Q about D, answer as short as possible. Q about R give him deflecting statements. "I am not prepared to discuss that right now." Or what R2C said above.
You're right, you do need space from him. Unfortunately as coparents you can't do that in totality.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018
