A couple of people have touched on this, but it doesn't seem to have really been spelt out:
He is still abusing you.
There's a constant implied threat: " He says that no-one will stop him from seeing his dc every single day and if I am honest I don't want him to not see them as often as possible."
That's understandable, but it's destroying you. And it is hurting your children, as they see it destroying you, holding you back.
I understand why you want what would appear to be an easy life and for him to have lots of contact with dc's, but he's creating and maintaining a different form of control and abuse.
I think you need to keep taking radical action on this. I think you need to create further space for yourself.
I would highly recommend you cut all contact between you and him, and set up contact for him via a supervised contact centre - via this website.
At this point, the old him, which he has left behind, will doubtless re-appear.
Two very useful numbers, both for National Centre For Domestic Violence: 0800 9702070 for general calls, 0844 8044999 is 24 hr emergency line.
They can sort out free, emergency restraining orders etc.
Yes, your head is a mess. But you are moving forward - asking for opinions, recognising problems and issues, looking for further support, these are all behaviours of someone who is looking to deal with and better their situation. And you are taking responsibility for sorting it out, so massive kudos to you.
Regarding that, 12 sessions ain't much, but far better than nothing, and a good start. I got hooked up with a counsellor via MIND - free, and no limit to the number of sessions
If you're not already on them, don't be afraid of anti-depressants. Your brain's chemistry has been changed over many years, so it needs certain chemicals to be boosted / replaced so that you can be better able to cope with your situation.
Lastly, I'll also re-iterate that you should get in touch with your local Domestic Violence Centre. Life is complicated, and I would hope that they will be able to co-ordinate things for you.
You're doing fantasticaly well.
What has happened to you has been due to others. It may be your responsibility to deal with it, but it has been caused by others, and you are dealing with it.