"Maybe because I was brought up in a very verbally abusive environment where my mum would regularly call me the most hurrendous names, is possibly why I am not saying right that's enough it's over.??"
Possibly yes. The abuse you suffered here was not your fault, that all lies with your mother.
You do not mention your father here; is he still around?.
We learn about relationships first and foremost from our parents, look at what yours taught you here. Now you're being verbally abused by your now fiance and he sounds very similar to your abusive mother. Your boundaries, already skewed by childhood abuse at the hands of your mother, are being further got at and otherwise eroded by this man now. This is likely why you're not now saying to yourself that its over.
This is not what you deserve from a relationship.
I sincerely hope you do not contact your mother these days.
How can you be helped here into leaving your abuser?.
Remember always that the only acceptable level of abuse in any relationship is NONE. She let you down here abjectly as a child and now your fiance is behaving similarly.
Do not further act as some sort of rehab centre to such a badly raised man. I would also think he does not have anger management issues because this treatment he metes out is for you and you alone. He does not treat work colleagues like this does he and he's probably also quite plausible to those in the outside world. Also anger management is no answer to domestic abuse which is also what this is.