KMBAR
Welcome to HealingWell. I am sorry you are in a bad spot right now and I am not judging you here. I am just going to turn on the lights for you so you can see what I see in your post.
You lived together for 10 years and the last couple of months you were angry and upset yet you thought not a lot of putting him down and not taking into account that your comments were spiteful and hurtful to him.
You admit you felt bad but you never told him you did not mean it and you did not appear to stop the behavior.
Looks like he took you at your word when you kept telling him to go and you did not want him.
That KMBAR is verbal abuse. When someone puts you down over and over you start to believe what they are saying.
I think telling him the truth and apologizing to him should be your first step. He may forgive you but will he forget what has happened, I don't know.
IMHO I feel you would benefit from a good medical exam by your Physician as it does not strike me that you always treated him like this.
Getting your feelings hurt because he is leaving and you told him too is very unfair to him. And telling him he can never see you again................
Please see your Doctor as you may have a mental health issue going on and therapy may be your answer.
If you do talk with him and he stays then talk straight to each other, communicate.
As far as his Mother, I am sure she does like you but any Mom will stand by her own child first and I do not read anywhere that he abused or mistreated you.
I wish you the best and I hope you reread your post and see where you need to make life better.
Sincerely
Kitt