I've just come into this thread, firstly you are well shot of him.
Right, abusive men are addictive. It's been just over 4 years since I left my husband but I think about him all the time, I found out he's married and had a baby boy at Christmas. I slightly feel sorry for the woman and child, but part of me feels jealous, not of their relationship I'm not really sure what of tbh. It takes a lot to stop yourself from going back there and you have to make it a daily decision.
This man was most definately abusive. Read what you have written and substitute it for a sister, best friend, daughter etc and ask yourself what you would do if it was her. My new BIL is treating my sister badly (not like this or how I was) and I am getting really mad about it, so far I'm keeping quiet, but I know I will do something if it gets worse. You are worth more than any of those women because you are you, you are the only you you have and you have to live with you for a long time. We have for a long time put ourselves last, it has come from a religious time when people took "love your neighbour as yourself" to mean you loved them more, but you can't love your neighbour if you don't love yourself - religious or not.
I don't agree with anyone who said you shouldn't have written to his mother or tried to make contact. If I was engaged to a man I would want to know my prospective MIL and I would hope she would want to know me. You are going to be part of this woman's life for a long time, give her grandkids and the man you love loves her and that makes her someone special. Also she has shaped the man you love and want to marry. If my fiancee was keeping us seperate I would make efforts to see her.
As for therapy, it is no wonder your anger has gotten worse while you have been with him, I know mine did and then I got into another abusive relationship and it got worse again. With TD (TinkerbellesDad) my temper is now quick when things are down because I'm defending myself from what I percieve as a potential threat. I am having help with it but there are other problems here. Your ex said you need therapy as a way of getting at you and carrying on his control by making you question yourself as a mother. Whether you actually get therapy is your decision. You have just come out of an abusive relationship and councelling could be helpful to you to help you to deal with it and to sort your temper out if it is still a problem when he's not involved. Speaking to your GP is the first step and if you haven't told anyone else it would be good for you to actually say the words out loud to someone.
BTW if you are depressed (which you could be after that and if you are it's his fault) or have anger management issues (same as before), it doesn't make you mad. What would be mad is staying or going back to him. If you do that then you really will need assessment.