The thought of looking inwards scares me (because it means not everything was her fault and I must take responsibility perhaps?) and I would have to deal with reopened childhood wounds bought into the forefront by this r/s.
Being honest with yourself about this part is a great step. I don't know if this will help, but I'll offer you some perspective on where this could take you.
It is going to be very hard work. You are likely to be feeling more pain and discomfort than you ever allowed yourself to experience before. So you have reason to be scared.
Whups, that wasn't very encouraging.
Here's why it is WORTH the effort. As you come to peace and understanding after you go through the hard part, you will be leaving your fetters behind. You will be able to go forward into all your relationships: romantic ones, friends, coworkers, family, without this monkey on your back, without the stuff that messed them all up.
As you examine what got you there... .what hooked you... .where the void in you that you were trying to fill with somebody else was... .you will find your path to freedom from it.
I speak as somebody who has been processing the end of my marriage in a very strange fashion for five months now and finally got her belongings out and our joint belongings in our formerly joint home resolved this week. I've been through an incredible journey so far, and most of it has been about myself and things that predated a marriage of a couple decades plus.
Do you have an individual therapist for yourself? That can be a huge help. (I don't frequent the Leaving board, so I don't know your history.)