lonemum I don't think that's what anyone is saying. It's not to do with just what he wants, or just what you want, it's to do with what is best for your child. And that has to be repeated over and over. It has to be at the heart of all decisions.
I know it's very difficult, especially if you aren't getting on and your XP isn't listening to advice or is getting agitated. I know it likely goes against every fibre in your body to agree to not see your child for extended periods with someone you don't have confidence in, but he is the dad, and he seems to want to play a decent part in dc's life.
We've all been here, trying to negotiate how to agree access with our ex from one side or the other.
Often in these cases it's neigh on impossible to sweep away all the past conflicts that have nothing to do with the child. It's like you have to have a massive conflict negotiation before it even gets to the child. But if you can't resolve those issues it's going to make the next 18 years harder than they might be.
It's in everyone's interests that you somehow manage to get to a point with your XP, and he with you, where you can just focus on dc. You have to be able to communicate about routine, remain flexible. You have to bite your tongue so much it's in danger of coming off !
If he is really truly wanting to co-parent and wants more than 3x four hours a week, most people would see that as admirable ( assuming he's doing so because he loves his child ) . But if you say to him 'I won't allow it' he's going to get the hump which helps no one and leads to conflict, and stoke bad feeling in him towards you.
If you were able to get from him ( and it's essential really ) a proposal of when and where and for how long he wants access at least you can work from there and negotiate from that point. You don't have to agree. But if he feels like he's part of the discussion rather than being told how it is it might defrost things a little.
But don't just say to him you can have what ever you want, you just have to constantly frame everything with 'what is best for dc' and let him have his say even if you don't agree....