It must be extremely hard for an individual who has spent a lifetime believing something to admit to themselves that they have been misled all of those years .
Yes, it's known as "the sunk-cost fallacy": The more you have invested in something, the more sacrifices you have made for it, the less likely you will objectively evaluate it and the more likely you will feel more convinced about it because the alternative view that you are wrong is too horrible to live with.