@Imi9 you are pretty much were I was 6 months ago after fleeing my emotionally abusive, coercive and controlling husband. He emptied the bank accounts too. He also found out where I was and covertly came and took my car away with the spare key, blocking it in back at the family home with his car. He also made it difficult for me to get our belongings out of the house.
I won't sugar coat it, it's nasty and still is, but he has broken the law. I, like you didn't wish for him to be arrested because he would loose his job. I did report it all to the police though. Please do this, so it's noted, as he may well get worse. He wants a reaction, he wants to control you still, he may up the anty. I hope he doesn't but start the paper trail now. It's good you've got bank statements printed. If he does contact you keep records of it.
The police can also signpost you to help, such as victim support and woman's aid, even if you don't press charges, they in turn can help you apply for benefits while you get sorted and offer lots of support and practical advice.
I didn't fully grasp the emormity or seriousness of what he was doing to me and my child until I was away and started telling people. You will be in survival mode, specially whilst trying to protect small children. There is probably more that you have buried.
You will be OK, you will be able to claim UC, child benefit and your 3 year old will be entitled to free preschool hours. I'm back at work now and although it's been hard it's 100 times better than living with someone abusive.
You've done the hardest bit by leaving, it's a long slog now to organise everything but I promise it'll be worth it for you and your children. 