Today ex H came to pick up ds. Ds has Aspergers. On arrival he asked ds if he had brushed his teeth. Sounds minor I know but this is a question (among many many others) that he constantly asked when we were together as he often called me dirty and said I was a poor parent for not brushing teeth immediately after breakfast, I usually wait twenty minutes because of acid straight after eating. When this question is asked it IS a trigger question and ex knows exactly what he is doing.
Because of his condition ds often needs help with questions like this so he turned to me and said "have I brushed my teeth Mum?" to which I replied "yes of course like you do each and every day, in the morning". Ex H then asked me where ds's phone was, he has a mobile to keep in touch with his Dad. I asked why he wanted it, the reason being that Ex has many times in the past just kept ds's phone because he has lost his own and I have had to replace it at least four times.
The argument escalated and he called me a "cunt" not in front of ds thankfully. I told him if he called me this again then I would call the police and have him removed from the property as he was being verbally abusive towards me.
He then carried on getting ds ready to take out and I asked what time he would be back with ds. He ignored me and then said to ds "I can't talk to your Mum anymore because she wants to call the police and get me into trouble when I haven't done anything just like she did before, remember?" I called the police before when he had me round the neck and was throwing me all over the living room in front of my kids. He then said "I can't have any more dealings with your Mum because she is nasty and trying to always get Dad into trouble so from now on I will only talk to you and you can tell Mum what I want to say".
He also said "Oh and if Mum called the police then Social Services will be involved and the shit will hit the fan". There were other things as well, all to ds but aimed at me. I just smiled at ds and told him that Dad was being very silly today and he wasn't to worry about it because even grown ups, like us Mum and Dad (I included myself) could be really silly at times and he should take no notice.
Anyway I don't know what the best thing to do now is. This isn't the first time and I honestly never thought he would be THAT kind of father. He seems to have no conscience whatsoever about saying these things to ds and I find it absolutely sickening. For him not to say them I have to just shut up and accept anything that he says and does. Ie the dig about tooth brushing, which yes I should have let go but should I have let him take ds's mobile YET again?
Please give me some pointers on what to do now. He also constantly holds Child Support over me as well, threatening to stop it all the time, tells me I don't deserve it like I am spending it on f*cking shoes and handbags or something 
. He is just such a cliche. Every penny of it goes on the dc or bills and he knows this just uses it as a stick to beat me with.
Sorry this is so very long. Just feel so rubbish now and ds if off out with him listening to god knows what 
.