Wait till your own child pretends to not know how to put on shoes or get dressed. It's a relatively common thing for a child that age. They are growing and sometimes feel a little insecure so revert back into being a little more needy. Basically that is pretty normal. The child is three...that is innocent.

Yelling, swearing, hitting and pushing belittleing him and calling him names...yes you do need to get to therapy. I don't mean to be rude but it sounds as tho your behaviour is out of control..like you are having tantrums yourself. This child did not ask to be here, he did not ask to have you in his life, or the parents he has. He doesn't have a say in any of that, but you do. He doesn't have the skills or tools or emotional maturity, he needs parents to model that to him.

Perhaps if you try to approach being part of his life as a privilege and not as a burden it might help. You could be a positive healthy influence in his life or you could be a negative hurtful influence
But it seems he has enough of that already. You have to be the adult tho, and saying that you know you should go to therapy, but are afraid to because you are afraid of the consequenses for your actions... what message does that send to a child? You know you need help, ask for help. There are parenting classes and therapy to help you deal with your feelings in a positive way. It's not this little three year olds fault. It sounds like there is a lot of resentment but it's being targeted where it doesn't belong.

Try to think back to when you were three? I do not understand why you hate him, he is three. Ever have siblings, fight with them when you were little? Sounds like he needs some guidance, dicipline ( not yelling, screaming, belittling, or hitting) and some love.

If you feel you cannot give him that or control your anger then perhaps you need to step out of the picture so that he does not have to deal with that as well. You do have to acknowledge who is the adult in this.

If my reply seems harsh it is because I think that it is irresponsible to acknowledge what you are doing and to continue doing it even tho you know it is not right. There are so many people on these forums that were treated poorly and as adults are still struggeling with the damage. Imagine this was your own child.. how would you feel about his fathers gf treating your child this way?

Child abuse ia never ok no matter how you try to justify it. So reach out and get help in real life. Raising kids is not easy, being in a blended family is not easy. But if it is what you choose then you owe it to youself and to him and your own child to get help. Lots of parents need help, there is no shame in that.

I guess think about how he might turn out if things continue this way, and how he might turn out if there is more peace and love in the home vs anger and hate.

I hope you will be brave and seek some help with this. I don't think you will be put in cuffs but you will probably be given the help and guidance you need to make a positive change.

What role is the father playing, it certainly is not up to you to be doing it all. Since you stay home I can see why that would become a frustration. I have been a stay at home mom, it is tiring and taxing that is for sure. But his role is very important and he needs to be giving his son as much as he can. You could both work on this together.