The ego is not just a belief
The ego is not just a belief, an idea or a thought. If it was so, it would be easy to be free from it. But this is not the case.
The ego is energy (essentially is desire), which identifies with the body and creates the strong sense 'the body is me' or ' the body is what I am'.
Due to this strong sense, we think and believe that we are the body.
The essential nature of ego is desire. From desire spring up all other egoic tendencies. The ego also causes all kind of identifications.
Pride, greed, like ,dislike, anger, jealousy, fear, ambition, gluttony, lasciviousness, vanity, avarice, etc., are all children of desire. The so called vasanas in Sanskrit are all these above mentioned egoic tendencies. Vasanas and desire are like a tree with its branches. The trunk is the desire and the branches are the egoic tendencies.
The stronger the desire and its children, the stronger the identification with the body and the sense of me and the egoism.
By dissolving the egoic energies we weaken the identification with the body and the sense of me and mine.
Who is free from desire is free from ego and all other egoic tendencies, because they are not different between each other.
That's why the sages have declared, ''Desirelessness is freedom and Self-realization as well''.