I totally get where you're coming from, as I got pregnant at a young age, listened to my Mother and spent a good 5 years living for her instead of me.
It has taken me until now to be able to finally move on. I spent years fantasising about the way she/he would have looked; sounded like; smelt like. It was torture for the best part of 7 years..
I suppose it is just different for different people in regards to why nobody speaks about it.. But I can truly truly understand the guilt you feel, because I also felt it for years. Totally understandable.
One thing someone said to me which really stuck in terms of 'moving on' (though you can obviously never forget), was this:
Acknowledge the pure fact that you actually FEEL so bad about it. To me, it shows you why you actually shouldn't be. To elaborate: you are feeling guilty. This shows you are a GOOD person, because if you weren't, you wouldn't be so affected by it to this day.
The way you move forward is by accepting the decision you took at the time. What I did was write a list of the reasons you made the decision. Don't write the benefits of having kept that child because the point is to help yourself move on, plus you already know what the benefits are 'cos you have children.
I also wrote a letter to my unborn, which broke my heart and triggered an emotional breakdown. But once I was finished writing it, I felt much more free and as if I had truly laid the baby 'to rest'.. Don't forget that it is still a loss, particularly when the decision to terminate isn't 100% your own. Maybe you never fully addressed the grief?
Hope this somewhat helped.. It's good to know that others felt the same as me tbh, because I thought I was being melodramatic for all those years, due to the culture of abortion and amount of people who use abortion as contraception in this day and age :/... When I was at the clinic, there were two girls. One getting the abortion and her friend. The pregnant one made the most horrific comment related to coathangers and doing it herself if they didn't hurry up, and was messing around and laughing in the clinic.. This was the most horrific thing to hear by someone who didn't even want to be going through with it :(
Good luck with everything and let me know if you did try anything I suggested! Xx