ok I've read the op of your other thread.
This isn't healthy.
You said yourself that there is no basis for the way you are feeling, so why can you not let go?
I suspect that you have some issues remaining from the birth where your baby was taken away from you and you were unable to be the most important person in his life for those 4 days before you got to hold him. Now you don't feel that you can be away from him as you feel you let him down when he was newborn?
You didn't. Sometimes babies need some extra help when they're born. It doesn't make you a failure or leave you needing to make it up to him in any way.
By refusing to allow him to go to anyone, even your dp, you are making him totally dependent on him, and teaching that he can never be away from you.
This is not going to do him any good.
You need to learn to let him go a bit, go for a walk and let dp look after him to start with, and gradually move away from having to have him there constantly.
If you feel you cannot do this alone, then perhaps you need to seek some counselling to help you come to terms with those days after his birth.