Couple more thoughts dear...
Everything that is hard, eventually happens when it's really TIME to happen. What Hops said about why some people hang on to things is true; but it doesn't mean that we're unable, or weak, or something. It means we haven't worked it all out yet; haven't made our peace with "what it WAS" and then decide that "what it can be NOW" can be very different. There isn't much better after "letting go" - because the past was what it was; no changing THAT. But what changes is YOU. You say say a final goodbye, hoist your pack, and walk on down a new path that you are free to choose what you take with you.
The other thing I forgot to say - but it was staring me right in the face; and is something I know as well as anyone - is that there are distinctly painful elements of grief all woven into the experience of abuse. What we know to be normal relationship doesn't exist in an abusive relationship - and that's a hurtful betrayal of the natural order of things. Why ME? What was wrong with me? What did I do wrong? When all along - it was the other person's inability to be strong and vulnerable enough to love. It's THEIR weakness - oftentimes because of abuse they suffered.
The fact that you and Bill STOPPED IT in it's tracks and didn't perpetuate it is a tremendous victory and success in your lives. No, no one's "perfect"... but you tried and did well enough that your children don't close you out; you have good relationships with them. You were strong enough to love and overcome your natural instincts to protect yourself with perhaps less-wise or self-destructive strategies. No grand gestures or miracles were needed, it was simply showing up and being open and loving every day that was your success. You made that choice; out of love. You can do it again - for yourself.
So grieving kinda exists "outside time". There is no rhyme or reason or recipe or prescription for what it consists of or how long it takes. My mom is still grieving her mom - over 50 years later - and it's one of the prime reasons my mom went a bit bonkers and became like a Dr. Jekyll/Mr. Hyde. Something broke in her that wasn't ever fixed. So, I've never really gone full "no contact" with her - because how could a person not have compassion for another who all these years later was still stuck in the same pain? I do however, protect myself... from letting it affect me so deeply that I can't be "who I am" with others.
It makes absolute sense to me, that your mom still figures so strongly in this time of grieving Bill. I think your key to opening the door to your understanding of the whole thing is already in your hand... and now it's just a matter of organizing it all in a way you have that "AHA!" moment and see your way to being free-er from it. It's a puzzle - some take more time than others.
Hang in there dear - and find those little moments of joy in each day, despite all else you think about and feel. They're there and it's OK to cry, wail, rage against the storm... smile and laugh and kiss the babies... unto total exhaustion. You'll rest & recover and start again. It's the way of things; in it's own time.
