Ending therapy

For all those who ever had therapy, when did you feel you were finished with it? I have very bad PTSD from an abortion. I did not regret it or anything but I was going through a break up around that time so I never really focused on what was happening. I also feared going through that ever again even though I got on birth control after. Now I’m about to have my tubes removed in a month or less which eliminates my possibilities of becoming pregnant (it’s 99.5% effective) and I have overcame a lot of my feelings towards my abortion. I feel I have control over my PTSD and that it doesn’t control me anymore really. So I feel I am ready. How did you all know when you were ready to stop therapy if you have?