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I think many people see the red flags and the behavior and just put it on the back burner because of the fear and worry that it brings by acknowledging it and also beating yourself up for missing the behavior and tolerating it. Early on in any relationship we often tell ourselves fairy tales and make excuses for behaviors that in our gut isn't right. I imagine you did this like many others when dealing with a tough individual.
The self involved, entitled behavior is most likely present, but each person does a good job of hiding it as much as possible and pretending it doesn't exist.
Whether it is narcissism or any other trait, it is not uncommon to see traits early on in a relationship and pretend they are not there in the hope that things work out, family is established, kids, etc.