I'm Done! I Think!

I have an adorable 11 year old grandson and his mother who is as cold as ice. This woman lied to my son about the existence of his child, then emotionally blackmailed me into keeping the child a secret. My son unaware that he was a father moved overseas to start a new life. It took me over a year to get "permission" from the mother to inform my son.
Last week my son returned to Australia and finally got to meet his little boy for the first time and things are progressing fantastically for the both of them.
This emotional roller-coaster has been taxing on myself although my struggle with this woman has finally concluded positively for my son, I on the other hand still don't have access to my grandchild. We were so close for years, then the mother cut me out of his life for a few years. This whole on and off access has screwed with my heart for over 12 years. Last week I put my foot down and cut ties with this woman. I just can't take it anymore. I will continue to be civil and polite for the sake of my grandchild and my son but I am getting too old to play games anymore.
Have I gone too far? I don't think I have but maybe I have ... I suppose I need support from other non-access grandparents because sometimes emotions get in the way of standing back and looking at my situation clearly.... Help!