I am glad you’re safe right now. Don’t concern yourself with what he thinks the future holds for your relationship. You are absolutely right about his controlling intention - the programme he is in can be required to report back on their assessment and they will absolutely understand what’s going on even if social services refuse to see it.
Write down what has happened. Be as specific as possible (dates / times / case ref.
for the non mol). The simplest approach is to break it down focusing on what HE has said and done. Make a start and then add to it as and when you can.
Include any relevant doctors appointments / mention any witnesses to his behaviour / if a relative, friend, neighbour, school ever voiced concerns then say so / any calls made to the police (even if you hung up) / any relevant vet visits for the pets. Other people corroborating wherever possible will help a lot.
Just bullet points might make it easier. Start a new page for each area of abuse eg.
Facts
physical harm to the children - on X day he did Y to child. I called police who attended. I was asked to make statement. I did/did not do so (delete as applicable) for Z reason.
Physical harm to me - On W day he did B to me. I did/did not go to hospital for C reason.
emotional harm - threats / isolating you from others / checking your accounts / threatening or hurting the pets. Screenshot any messages or emails from him which are relevant.
financial harm - what he contributes to the household / whether all bank accounts are joint / whether you are allowed to access them / whether you have access to your own money
sexual harm - if he has ever hurt you in this way add it here.
Feelings
Impact - impact this has had on your other relationships, your well being, your finances, your health, your kids. Any medication you’ve taken since with him, any therapy or counselling you’ve sought to access.
I know you’re motivated by keeping the children safe, but the children need you to be ok as well - this will help them. So even if you don’t feel you should be a priority remember that THEY need you to protect yourself too. Does the programme he is on provide you with a Counsellor as well? If not, can they help you access services?
I really hope you’re able to read the Lundy Bancroft book. It helped me to see what was going on clearly more than anything else.