I see you and I hear your frustration, you clearly need to vent, as you sound at your wits end.
Can I ask if it has always been a difficult relationship or did it change when baby came along.
I ask this as, any health worker will tell you that toddlers haven’t fully learned how to control their emotions. When they feel angry, it can come across as fierce anger, and may seem as if it directed at one person specifically and as counter intuitive as this may seem, its because you are their safe place. They are learning to express and regulate their feelings and you are the sounding board. Add into the mix his nose has been pushed out of joint as there is now competition on the scene, it can be very demanding.
My mate is in a similar position, she has just had her 2nd son and son number one keeps asking when he is going home...its sweet and funny to me, but she is at her wits end.
What I am hearing, despite your claims to hate him, is the very opposite. You do what he needs, not wants, as it is in his best interests (no black teeth for him!) and you clearly have his best interests at heart. It also sounds like you know when to walk away, as you are having bad thoughts. Bad thoughts are something most parents have and some act on them, you have sought space away. That's not a bad mum, its a wonderful mum, trying her best, at her wits end and struggling to understand what has gone so wrong.
I maybe projecting here, but sometimes I get so exasperated and down, that I need to blurt out stuff that has been going around in my head, I don't necessarily mean it but I don't know what to do and whilst people listen, they do not hear. You feel you need to walk away not that you want to, you have just run out of ideas?
Are you a stay at home mum, does he go to nursery, do you have anyone to support you and give you some space to get your head around stuff?
I'm sending you big mental hugs x