I think you are so brave for putting yourself first. I hope you start to heal and find inner peace with your decision.
I understand some of what you are feeling, I plan on telling my husband over the weekend that I am leaving. He is also controlling and we just have so many differences. I need to be with someone that brings me peace and joy, not anxiety and depression. I do feel an enormous amount of guilt though, that I should stay, even though I know I will never be happy. He is 44 but not great at taking care of himself, or not after me being here doing everything for him for 5 years.
I hope everything works out for you. Try not to feel guilty, you have to do what is right and best for your own mental health. He has the choice to change and find someone new. That responsibility is on him to do so, if he does not want to be alone.
Hugs