How does porn not affect a guy’s(and woman’s) attraction to his/her SO?

I’m a 17 year old girl (never been in a relationship) and I’m trying to understand why people watch porn while in relationships. I’d like an explanation that doesn’t involve stuff like ” Every guy does it, it’s normal.” ” Get over it, it’s not about you” ” Good luck finding a guy who doesn’t watch porn” ” Men are visual and they like variety”

I just don’t get it. Why shouldn’t I feel bad about my partner masturbating to other more attractive women? How am I supposed to believe a guy when he says I’m enough? If he is looking up videos of blondes with huge boobs then how can I believe he is satisfied with me but looking for the opposite? Why does masturbating equal watching porn?

Why does it matter that he can’t actually sleep with them? So he wants to sleep with them but it’s all good cause he can’t? “It’s fine because he chose me” Are porn stars throwing themselves at him and he’s choosing me over them?

If a guy has videos of his SO, will he choose that over porn? I’ve seen a lot of answers that say no. So basically even the excuse of convenience doesn’t apply. If he couldn’t watch porn, is he gonna fantasise about other women too?

Why is porn so important for guys? Why do so many guys go through such extreme efforts to hide it? Why choose pixilated women over a partner’s feelings? I don’t really think forcing a partner to stop watching is a good idea. Though I’ve seen men describe it as insane and abusive , that suggests a deep attachment to porn that I don’t understand. I also don’t think checking other people out is the same as masturbating to naked pics of other people.

I’d appreciate an in depth explanation of how guys think of the women on screen before/after/during masturbation.