No more letters. That BS only works in the movies. If you really can't take the limbo anymore then set up the MC appointment and see where you stand.
Take some time and read JRUSS's story it has a lot of similarities to your story.
Before D I thought the same that I would live in an apartment and it would look like $hit because my ex did all the decorating and inside cleaning. It turns out I kept the house and made it better. Her sister was just in town and visited and said omg this room you redid looks amazing. My daughter and I are currently redoing her room together.
90% of your fears will not come true and I'll say it again being divorced is 1,000 better then how you feel right now. Do you see my signature? That's the mindset you will develop in time. It's a long hard road but a trip worth traveling.
Originally I was convinced it was all my fault. I was raised by a narcissistic father and unfortunately modeled some of his traits. But with time and space I can see now we were both to blame. Neither of us had the proper tools or role models to navigate a successful relationship. It's a shame because we both still have so many things in common. I truly believe that every marriage goes through rough patches and the ones where the people came from healthy families who knew how to communicate their needs and differences make it and the ones that didn't do not. Or people just stay unhappily married out of fear. Great marriages take a lot of work.
I know it doesn't feel like it but you will survive this and most likely thrive.