How often does he look at porn? Every day? All day? Once a day for how long?
I think alot depends on how often he does this and for how long. Personally I don't see the difference between looking at a Playboy magazine or looking at Porn. It's how often he does it and for how long.
You should be confident enough in his love that it shouldn't bother you. If he doesn't MAKE you confident enough in his love, that's another story.
Don't threaten him or withhold sex from him in order to get him to stop -- that's no way to get anything done. Withholding love is shooting yourself in the foot. You'll just drive him somewhere else. That's not what you're trying to do!!
Try to compromise -- ASK him if he'll designate a certain amount of time watching it, and let it go at that. Don't make him STOP. Just compromise. Just because he's watching it doesn't make YOU any less of a woman. You shouldn't be THAT insecure. You're still good enough for him. That's why he's with you! So stop fighting about it, ok? God bless & please take care. Hugs, Lee