OP, I don't know whether my approach to my (STBX)husband's temper loss was right but based on my experience....
My problem with your posts is that it's all I shouldn't hit him but here is what's wrong with his behaviour/our life etc. I don't see that as taking responsibility.
My husband would only discuss his temper loss in terms of what I do wrong. And I refused to engage in that. I wanted him to acknowledge that his loss of control was never justified and needed to be dealt with before we tried to fix our relationship. Otherwise I felt that it hung over me like a threat if I slipped up.
You insist you would never abuse your children. I am sorry to be blunt but if you have already hit out in anger I think there is a risk you could with them too. After all, it's appallingly wrong to do it to your husband.
My husband said he would never mistreat our children because they would never annoy him like I do. That worried me so much. It was a terrible answer. What about when they are teenagers for example, when they really work out how to push their parents?
I can see how it is scary to get help. I have never been 100% honest about our home life to anyone because of the fear of child protection issues. But you need to get help. I cannot see anything in what you have said here that puts you at risk of losing your children. So I think you are safe to go speak to your GP honestly and get the help you need.
And it may be you need to leave and make changes so that you are happier.
I'm sorry you are so miserable. really. But hating yourself is easy, taking responsibility is the tough bit.