Silver...
There's going to be lots of folks giving you solid advice, and I hope you are able to follow some of it.

My own feeling is that I need to be honest with you, and I have no intent to hurt you. Please understand this...
You have every right to grieve about what has happened to you, and to find out now another crappy thing he has done is so very hard!
That said...if this is the way he treats you, perhaps you are better off without him. I'm not implying there were no good times, but his actions now are not being respectful of you.
As far as your "friend." Your Mum was probably trying to be sweet when she made the suggestion.
But when you know that she does not treat you withe respect...why invite her??

Silver, you have a lot of pain to work through and it's not going to be easy. Grief, anger, tears of frustration, wild thoughts--it's not going to be a picnic for sure.
You Can Do It.
I don't you very well, but I admire you. You may not feel tough enough right now, but it will come to you.
Believe in yourself, please

Cap