Advice on how to deal with toxic ex

Just wondering how many other mums have tried to co parent with a narcissistic toxic ex, we have been separated for 2 years and currently going through settlement issues, he has brought the kids into it and telling them that he has to sell their things to give me money, my eldest is upset about it and my ex has another child who was in my life for 10 years who he has now poisoned against me ?
We are also fighting about custody because he believes it should be 50/50 he works 7 on and 7 off, while I find it's fine to split the school holidays 50/50, I have trouble splitting them 50/50 during the school week because he is careless about their education and doesn't have any involvement in the school what so ever! He is calling me selfish and greedy and really harassing me about it, I find the school days really disrupting to them and prefer him having them on the weekend, sorry for the long post.. just wondering if anyone else has been through this that could offer some advice, thanks