Ok, first off, learn to use a full stop. Jesus Christ...
Now onto the question. You don't stop him. Nto by asking, at least. He is a guy, he gets randy. He wants to feel a little naughty, and he has such a sex drive that he wants to go at it again after half an hour.
There is no way of you stopping that. If he gets bored, he'll watch some porn.
Twice a week is RARE, for most guys. Be happy he ony does it then.
The reason he likes porn is because it's FRESH, and not the same like sex with you or watching the porn you made.
It gets him off quickly and relieves his stress, and he can do it alone, his way. Think of it like reading a book rather than talking to you. Sometimes we just want to do things on our own.
He doesn't care about the women in the porn, just like you don't really care any more about edward from twilight. It's just a random fantasy. Would you rather he actually went out and banged other chicks?
I suggest you tell him you're going to stop having sex with him until he stops porn, if you really want to know how he feels about it. Or at least tell him to do it when you're not around, for the same deal.
He sounds like a bit of a ***** though. Watching porn with you around is a bit of a no no, and if he ignored you while you were crying, either you cry a lot or he's a bit of a *****. I would stop, if my girlfriend asked me to, but I'm not as much of a dog as this guy, so there we go.