Hey Joss. First of all, no being ashamed of yourself for not making him leave sooner. Those kinds of feelings only weigh you down. Best to let go of the woulda, shoulda couldas.
We are all responsible for those things in the marriage that we did or didnt do. To me, though, it has to do with intent. I did not intentionally try to hurt him or the relationship. I've learned we do the best we can with the knowledge and tools we have at the time. When we know better, we do better.
I am actually on another part of my journey, trying to figure out what matters and what fills me up. I enjoy spending time with my family, writing, biking, volunteering, taking classes and traveling.
I stood for years, but, I am no longer interested in reconciling. He lives 6 hours away and has his own life as do I. We are very different people. I have changed a great deal, he hasn't. As I wrote, he is still deep in the tunnel. Not sure if he will ever get out. I hope he does and finds happiness or this was all in vain.