You are an intelligent woman, this I can tell by your posts.
When you study for a test, do you study with your head or your heart? Obviously, your head. Your head (brain) is designed to do the thinking, your heart is not. You are trying to saddle your heart with a job it cannot do, and thus, the project will end up with an F.
You are only controlled by his emotions, because that is what you are choosing to do.
You are struggling with detaching, because, you do not want to do it, that's it. So, don't do it, days will turn into months, months into years and you will be in the same place, and if that is what you want, then that's fine.
There is a root to your not wanting to let go, and it's not all about your bf, it started long before you met him...only you know where.
Have you considered therapy? It may help you sort all this out.
I can respond to your posts for the next 10 years, but, you will do nothing positive for you, until you are ready.
Dolly