No contact after a year apart?

Hi there, Everyone seems fed up listening to me so I thought I’d reach out on the internet. I’ve been reading this site for a while but never had the guts to comments. My story:- 10 years together, 3 children, home business etc. The relationship had it’s up and downs but near the end he became very distant and caused a lot of fights I couldn’t do right for wrong basically. He left us June last year. I was devastated at first and fell into all the desperate traps you go through to get him back until eventually I broke and gave up chasing him and made a big effort to move on. I have been keeping busy I started going to the gym and still do I love it now it’s my head space, joined social groups, been going out more, I’ve been dating and have went through counselling. I feel good about myself again and have started enjoying the things I left behind for the relationship. I’ve stopped wallowing so to speak and I feel stronger as I go. He has been in and out my life since he has never really left me alone to grieve but he’s never asked for me back if that makes sense. We shared Christmas together and ended up sleeping together only for him to tell me the next day that it was just sex and I should grow up!!! Despite this I forgave him and tried to move on. 4 weeks after that we had a death in the family and he came to me. I supported him through this keeping myself above water to support him only for him to turn nasty on me again. My problem is and now I realise this – he has never left me alone he left me yet always makes contact. He seem so angry towards me and picks fights every chance he gets. In an attempt to go no contact and for my sanity 2 months ago I blocked him from my phone and email unless he had the kids I then unblocked it in case of emergencies. I’ve been called every name under the sun, I’ve been accused of having a boyfriend, I’ve been smeared with things that I haven’t even done. He blames me for everything that went wrong in the relationship and is generally really angry and hateful towards me when he was the one that left me. I feel so confused by this. He goes out his way to be nasty to me just last week telling me his new girlfriend has no children and that’s what is best about her. He’s been very nasty I hardly recognise him now and I don’t understand why. Male input here would be good. The contact with each other has obviously disintugrated since I blocked my phone which leaves contact one day a week (when he has kids) but in this one day he causes massive outbursts and fights over trivial things and has brought the old relationship up it’s madness that I can’t get my head around. My question now is do I go complete no contact and go through a third party for the children? Is it too late for the no contact rule with him being so angry to work? Will it work this late on? I’m so confused on how to deal with this. I’ve been civil and because of all the hurt and pain with the abuse since he left I am not sure how I feel about him and I was starting to think I was over him until he told me he had a girlfriend last week – I broke down for the first time in months – that hurt bad. I’ve not spoken to him since but I’ve never slept since either. I hate he has this affect on me still. Any ideas? Do you think no contact would work in this situation? I suppose I haven’t been in full NC as I have always responded to him. I’m so confused.

P.S sorry for the long rant – I did miss a lot out to try cut it down ? Thanks for listening/reading