Lilly, your shorthand analogy is spot-on! I get it!
The way it happened for me was this:
The life we had together (my X and I) was like a dungeon, dark and dangerous and awful, but I was used to it. He was like a smelly troll, but since everyone around us were smelly trolls, he didn't stand out. It was all "normal."
When he and I split, I at first missed what we had. I still, on some deep level, thought he was "normal."
I worked very, very hard to get out of the dungeon. I build new things into my life -- Joys that I had always wanted for myself, people and things I loved, service to my neighborhood, new skills like writing and painting. I found myself in this clean, bright, beautiful space -- my life's whole scenery changed.
Then, when he tried to walk back into it, he was no longer normal. He stood out against my new, better life. He was tracking his sh** on the floor, his attitudes still stunk, he smeared me with his dirty hands when he tried to drag me down into the drama again. And he wouldn't go away...it was horrible. Here I was with all of this brightness and promise, and this troll kept sneering at me from the corner.
THAT'S when it all clicked for me. HE didn't change, I did. His life (like your husband's) was still this sickening swamp, but I had changed mine so drastically into something I
LOVED that he had no power over me any more.
Sending you hugs, and wishing that your stay in the smelly dungeon is over soon. Keep building that new, brighter, fuller life, and you may find yourself less and less interested in whatever mess he chooses.
