What would happen if you said "no" to your ex? No, our daughter is not going to live with you. No, she is not going to have overnight or unsupervised visits. No, we are not getting back together in any way. No, we are not going to discuss this any further. I have retained a lawyer and you may wish to do the same. Goodbye. Go away.
One piece of wisdom I found on this site is that the best way to see the true nature of an alcoholic is to watch what happens when you tell them no.