Co Parenting FAIL

[tweedlezee]

Hi, I am about to have a little bit of a public rant so I am sorry. But if anyone can find it within themselves to give me any advice I would be hugely grateful. I am a mother to two a 5 and 6 year old (girl and boy) their Dad and I separated (were never married) 3 years ago. He was emotionally and occasionally physically abusive, during and for some time after we broke up. He has met another woman and they have a baby - this was all within 8 months of us splitting, she moved in with him and the kids who spent every other weekend and one night a week with him.
He decided he wanted to have the kids more, a 50/50 split. I agreed with the understanding that half the time - half the work. My daughter has just started school and the 'half the work' aspect is beginning to slip (from my perspective) and he continues to take any opportunity to be emotionally abusive towards me (parent - child dynamics are constantly in play).
Part of his decision, he emailed me to say before the 50/50 split was decided, was that he would not need to pay me any maintenance according to the CMS. I agreed to this on the understanding that he paid for half of everything. He doesn't do this. It is just another chance to be cruel and in power in our interactions. He uses these things to goad a reaction out of me and yesterday he got it. I feel a fool but there is only so long you can be surreptiously bullied for. I changed my telephone number because he was trying to get into an argument about lunchboxes.
The contribution towards all the clothes and shoes I buy were a pair of shoes which he gave me £10 for.
Is there any advice out there how I can move forward. I cannot sit in mediation with him because he lies and gets called out by the mediator - happened last 2 times so I gave up going to that with him. He then called around for a new mediator who was a man because the woman was twisting his words and tried to convince me to go, I didn't go.
I am stuck because my kids love their Dad, they love their step-mum and their new brother. They have a wonderful time but they are tired out by the to-in and fro-in and would like that to change to 2 night - 2 nights. I have a really good relationship with my kids and we talk openly and with ease. I have approached him on several occasions asking if the routine can change but stay 50/50. He ignores me. Plain ignores me. No response. But I had £50 of his money which the school returned to me for him and I got a whole weekend of messages about how I had his money, how dare I have his money etc. But then when I asked about half term he ignored me again, I have asked over and over and told him what days would be best if he had them so I can work, but ignores me. But he can abuse me about how I have his stuff. It feels like the material aspects are the look of being a good Dad is more important than the substance needed to be there for your kids. I don't know how I can carry on like this. Can I get in touch with the CMS? Can I get a solicitor to write to him to tell him he has to respond to me? How can I co-parent when he will not speak to me? I need to know where my power is to move forward because I cannot go on like this. But I also struggle to talk to him because of our abusive history.

[MommaGee]

What is your relationship like with the new woman? Is it possible for you to talk to her? She too is probably in an abusive relationship with him so might be easier to go through her unless it makes her life harder with him