I had this silly idea, that completely depends on OP having played fast and loose with the various -fixes. Given the somewhat frivolous fixations in the title, I'm willing to give that theory a chance:
Are you, perhaps,
My prefix is not real.
int data type can store only integers, not real numbers
My infix makes you more judicious.
The INT stat (short for intelligence) will give you better judgement in many role-playing games.
My suffix is the suffix of the superfix of a holy man.
If you superfix a holy man, you get sa'int (stress on the newly created second syllable), whose suffix is "int"
Despite these divisions, my whole is indivisible.
The whole ("int") is too short to be sensibly split into pieces, which explains the various "-fixes" actually being the whole word.
Yes, I do realise I may be wildly off the mark with all this :)