It's a tough one, Em.

He's reacting the way I did when I first felt brave enough to have a relationship. That's a long time ago, but your post reminds me how challenging it was. Little things, like being grabbed, or being jumped out on (while playing ) could make me freeze / run / burst into tears.

And yes, hypersensitivity to criticism.

I held part of me back for a long time, within the relationship. Out of terror that he'd leave Only his endless kindness and reassurance wore me down.

You know all this; that he's testing you, pushing you to see if you'll turn on him the way loved ones have in the past.

At its best, this can be an opportunity for him to learn how to express his badly-repressed emotions. Anger will probably be the main one. The silences are, at the moment, the only way he's been able to express anger. In a violent family, there's often no other outlet.

My partner was mature for his age, and was an absolute rock for me. I'm so grateful.

But we were really in love. With this being a new relationship, you might decide this is too much for your own mental well-being.

It might need a counsellor for him to hear that he CANNOT call you a liar.

That seems to be the big sticking-point.

He needs to realise that you can't go forward with him if he's not able to control that impulse.