@yl,
You're normal
While an interest in pornography hardly makes your husband abnormal, anything taken to the extreme is problematic. It could be addictive behavior but don't jump to that conclusion simply because you don't like it. If it turns out it's an obsession with him, then you have a big problem.
From my experience, it's fairly typical for women to insist (and if you're constantly fighting about this, "insist" is not too strong a word) that men give up a habit or behavior which the woman neither shares nor understands; simply as proof of his love for her.
Examine why his behavior upsets you.
If your sexual relationship with your husband is wanting, then there may very well be a problem.
If he is satisfying his sexual urges through porn rather than with you, his wife, it's a problem.
If, on the other hand, you feel happy and satisfied with your sexual relationship with your husband, what difference does it really make that he gets something extra from watching porn?
If it's about control, that an entirely different problem and even if he give up the porn, it will surface again about something else.
If he doesn't think there's anything wrong with it, and he stops because you insist, he will resent you. If he doesn't think there is anything wrong with it, he may not stop, but he will still resent you for trying to control him.
Of course if you are truly convinced there is something wrong about it, and he has a different opinion, then you have a major compatibility problem.
So often The Love Lorne on A2K post topics wherein they describe a truly horrific spouse but they insist that they love him or her despite the truly shitty behaviors. I'm not sure why this is, but it's very common.
You say you love this guy, and probably you do, but examine your love for him.
If he's really a great guy in almost all ways, and this is the one thing that bugs you about him, do you want to lose what you have over it? No relationship is perfect, and no two people are perfectly attuned.
On the other hand if what you think is love is simply neurotic need, then your marriage was doomed from the start.
Bottom line is that no one here can give you really good advice, because we can't possibly understand, with the little info you have provided, the nature of your relationship with your husband and his attraction for pornography.
If this feels like a problem that could destroy your relationship, then the best advice we could give you is to seek professional counseling.
This could be tough because your husband probably won't feel comfortable talking to a third party about his porn habits.
In any case take some time to think about the entire situation and be honest with yourself. Question your feelings and wishes as much as you question his.
Good luck.