I went through your post and the responses and there are some very helpful suggestions. One thing that helped me enormously after my break up with a controlling ex was to do everything he had forbidden me to do. I still celebrate the day of our break up and call it Independence Day. Instead of mourning the demise of your relationship is it possible to see it as a celebration, the end of a bad chapter? Maybe go to a restaurant by yourself (corona permitting), order your favourite food and drinks, eat dessert, buy some expensive cologne, basically do/buy anything you enjoy. Indulge in some major self care and remind yourself that you are worth it. What doesn't kill you et cetera.

If this feels unhelpful please ignore. I do not intend to invalidate your pain. Just sharing what helped me.