I propose that your behavior is not caused by flawed methodology but stems from certain acquired beliefs about your self worth, that you should try to address to solve this "problem".
Reason for Behaviour
The need to
- read everything stems from the need
- know everything which stems from the need to
- not miss anything important/useful which in turn stems from the need to
- submit the perfect paper or thesis which stems stems from the need to
- get appraisal from your advisor or peers which is a
- source of happiness
Thus, unconsciously you are afraid that, if you miss some information your work will be less than perfect and you will not get the approval that you are used to get. People will be disappointed, saying something like "This is not the quality of work we are used to get from you".
It is usually hard to change these core beliefs about ourselves, but you could
- realize that even with a non perfect paper you will be much better than other researchers (if the need to be the best is not something you can change)
- realize that your advisor values it more, if you finish your research in time than making the best work possible ("Better done than perfect"). Therefore you will get more appraisal for finishing quickly.
- look for other sources of happiness and validation in life that will make imperfections in your work seem less important
- friends that value your company
- spouse that loves and values you as a person
- teaching, where the amount of knowledge you need to acquire is much lower and the reward (admiration from students) is easier to achieve
(Disclaimer: I am not a mathematician)