My children's dad is so controlling and abusive what should I do ?

I have 2 kids with my Ex they are 5 and 4 years old. We split up two and a half years ago. In that entire time he has been controlling. He would randomly show up at the house complain that it was messy and stay until I cleaned up. He questioned me over what I feed them and tell me what to feed them. He has become a...