I have always been a very emotinal person. As i got older (as I've said in other posts) I thought of it as being compassionate or empathizing with others (putting myself in their shoes, as you said mike). It seems so crazy now that I always really took pride in the fact that I thought I was a good person for doing that...taking on the feelings of others. I do realize it wrecked me and brought me where I am now. I wonder where the balance is. Is there balance with that? Or should people just not do that?
At any rate I wanted to put in my 2 cents. I can get wordy, I'll try to be brief...and hopefully it will make sense.
Mike-I think it's great that you seem to really know in your heart/gut that your mother wasn't trying to hurt you. It's great that you realize this. But, I think that you still need "clear the air" so to speak. I just think that these things can creep back up....even if you push it down for now. I am not suggested that you lash out at her or yell at her, or approach it negatively. I just know that I have pushed things down, and stuck some duct tape over it...and after it rains a little....
I don't wnt for it to be a viscious cycle for you. And we are not talking about mom not getting you a gift you wanted, or making you eat brussel sprouts. This is something major...and she knows too.
She may also like for you to clear the air and talk with her about it. I know it will probably be uncomfortable at first. But just imagine the weight lifted from BOTH of you. I am sure that she is being consumed by this, and it seems like it serves as one of what I call...a monster (for you). Something you hope you can continue to deal with...but it's still there.
Like I said, I'm not promoting it as a confrontation at all. Just something that needs to be discussed. Let her know that it is something that you have struggled with and that you know she has too.
It may seem twisted, but I think that she may be relieved...you too? Especially if it is something that has always been hush hush, or avoided. Just think of the tension and what kind of energy is being brought to the table. I think that in order to clear the negative emotions, you should try talking with your mom.
That's just my opinion, and it may be bad advice. But the 2 of you cannot live harboring this...at least not happily. Just remember that karma is balance, not vengeance and it spans many lives...not just the current manifestation (known as your life

Oh, I got wordy! Sorry
My main point-these things can creep back in at a moment when you feel emotional...Its like a tornado for me...grabbing little bits of everything, as it tears through. Things you thought you were okay with can come right back (the monster).
That's just my opinion....take it for what it's worth.
I wish you the best, and hope that the pain showing up as anger...is soothed.
Together we stand; divided we fall...