How to co parent

I hate his guts but I want to be the bigger person and I don’t want him to hate me and be in even more bad terms with me than we already are. How shall I act when he’s In touch about our child I don’t know if I should be nice about things or jst be mean and ignore what he wants from me with our child. I feel like I need to be mature and nice and maybe he will realize I am not the crazy baby mama he thinks I am but at th same time I don’t think he deserves time being nice to him he put me through so much pain :( idk he said some really horrible things to me and about me when we broke up I don’t want to act like it’s ok for him to treat or talk to me that way