Your story sounds so much like mine it's eerie. I don't know your motivation, heck it was difficult enough to sort out my own. Here's what I discovered after many months of therapy. Don't know if it will resonate with you or not.
In my mind, divorce=failure. Throughout my childhood, both my parents looked down their noses at people who were divorced. Partly a generational thing, no doubt, but also a way to make them feel better about themselves. I absorbed that belief without ever realizing it on a conscious level. I didn't want to be "one of those people."
I was also extremely resistant to letting go. Not so much letting go of him, but letting go of my dream, my idea of how my life *should* be. Somehow, I believed that with enough determination, I could force the outcome I wanted. What a stress-filled existence that was!
Many other things, but those were key. Mainly, I needed to examine my beliefs and decide if they were really worth keeping or if I was just conditioned to believe certain things. Once I started questioning myself, I found I could let go of a lot of stuff that was really not serving me.
L