Ah. :-/
Give up on any expectation of mutual agreement. You cannot force anybody to agree with you. You cannot make him do the right thing. You cannot make him be reasonable.
An unreasonable x does not become more reasonable after you've left him (or split up or whatever). This I know for sure.
You honestly just have to accept that you are now in complete control of your own house and your own life and you make your rules and you decide on your boundaries and your style of parenting. That is what is in your power.
There is so much advice out there about ''co-parenting'' and it's useless to 95% of couples.
I had to leave my x because he was so intransigent and so controlling and so abusive and so disrespectful to me. Co-parenting was not on the cards. He was not going to become a different person and suddenly compromise and meet me in the middle.
Most women (on mumsnet anyway) don't leave because their partner if he is really respectful and reasonable generally , but there is just this other issue, unrelated to respect and reason that caused them to have to split up. It happens, but it's rare.
The whole notion of amicable co-parenting is another high standard for single mothers to try to live up to and feel bad about not accomplishing. The fathers aren't feeling failures for not co-parenting. They're blaming their exes for everything.
I bet your x feels no inclination or no pressure to meet you in the middle!
Just forget about his house and his parenting style. Honestly, my x is a nightmare, the most disrespectful and controlling partner you could imagine but I cannot try to control how he parents. It's rare enough mind you.
Have faith in how YOU do things.