How do you feel when you are getting a lot of attention from people that you find attractive, sexy, interesting? I am not saying you are an attention mongul, but porn for many is an acceptance of sorts that even if they can't get this in their lives on a real basis, the fantasy feeds the ego and the need for feeling something. If we depend on others or other sources for contentment and acceptance, recognition, feeling, we are never going to be satisfied because it is not real.
Porn is not real sex. Porn is mental sex. Flirting and dressing provocatively, attracting attention whether in how we dress, how we speak, the company we keep, are all symbols for status and a feeling of being in control over our lives. I believe porn to those guys that have used it as a source of sexual entertainment and sexual pleasure are only as guilty as the way girls have used their sexuality to get what they want. So in fact, when your guy says its normal, it is for a boy; like batting eyelashes is for a girl.
Now that being said, does this make it right or good in a relationship and can it harm or affect it in anyway? Well, there are things that may need tweeking when we get involved with someone but I truly believe that the sacrifice is not that difficult if the relationship is worth preserving. That takes a lot of time and maturity to come to that conclusion and I don't think he is there yet. Good luck.