This is exactly when you need to be crying on shoulders and unburdening yourself. It's what makes this place so important.
It's great that you are willing to go further than your mother and grandfather did: to admit that a problem exists and to tackle it and end the cycle. That takes such guts, and also such self-love, that you would go through the pain to make your life better.
I understand what you're saying about feeling as though you either have to swallow the sadness and anger or go through cycles of feeling them and getting nowhere. I just want to reassure you that there is another possibility: that you feel them and release them.
In my case, my abuser made me both a victim and a caretaker of HIS needs. It was difficult for me to put my needs first, because caretaking become ingrained in me. Even when I managed to push him out of my life, I still took care of others: my family (who couldn't come to terms with what I told them happened), my kids, etc. But I didn't really know how to look after myself in a non-critical way--I didn't really believe I deserved it.
I felt as though having been victimized changed me in ways that made me different from other people. But in a way, I was clinging to what I knew. I didn't realize it, but I was afraid to think of myself as NOT a victim, as just an ordinary human being who goes through the suffering that's part of the human condition.
What I'm getting from your "vision" during your walk is that you, too, are at a point where you would like to throw away the burdens your mother laid on you. But you don't know who you'd be without that story, without the anger, without the caretaking--who you'd be if you were just FMV, without the victim-story. It seems as though the anger and sadness won't leave you, but isn't it possible that you aren't quite ready to shed them--because it seems as though that would have to leave a void.
I think it is possible for you to stop pulling the wagon, once you're ready. Forgiveness is a way of changing the story. If you imagine taking the wagon to some place your mother would have loved (a cathedral; a cottage by the lake; some place where she was happy) and releasing her into the care of some beneficent force (Jesus, Mary, her own Higher Self, the spirit of her golden-hearted mother...) in a loving manner, how does that feel?
((((HMV)))) I know it feels as though you're been going around in circles, but I think you have made a lot of progress, even if you can't yet see that.