Smallbear, my dad committed suicide in June. How you are managing to survive everyday on top of putting up with an abuser is beyond me.
Take things one hour at a time, one step in front of the other. You WILL get through it. Your grief for your dad is just starting, and there are millions of unanswered questions he has left. Many will never be answered, but bit by bit you will make peace with it. Any feeling you have at the moment (anger, resentment, desperation, hatred even) is normal, you need to experience all of them to find the light at the end of the tunnel. And light comes with acceptance. I am not there yet either, but I know it will come.
Your husband/partner(?) is just making things harder by his behaviour, and you are making them even harder with your feelings of shame/horror at letting him do this to you again. But please be kind to yourself: you are at your most vulnerable you have ever been. The situation you are going through is a nightmare and no one could be faulted by not doing things "the right way" in your shoes. The fact you are alive and surviving, and taking care of your kids, and keeping alive is an amazing achievement already.
Please do not try to fix anything right now. Survive. Go on. Eat, drink, hug your children. Your world has been shaken and is in tatters, but it will slowly come together. Do you have any good friends? Please call them and ask them for help... just meeting them for a coffee or a walk in the fresh air will make a massive difference. Bit by bit. There will be setbacks and days where you don't want to wake up in the morning, and even getting out of bed will seem insurmountable. But they too will pass.
Big, big hugs and all my support and love, please PM me if you think I could be of any help.