Just because your husband watches porn doesn't mean he's addicted to it. Something like 80% of men regularly watch it. Sexual addiction (including porn addiction) is another thing entirely and affects a very small percentage of men. Also, most men who watch porn do so in addition to having plenty of healthy sex in real life, meaning that your husband watching porn doesn't necessarily have anything to do with not having a sex life with you.

So, it sounds to me, based on what you've written here, that the real issue may lie with you, not your husband. It sounds like him watching porn bothers you and makes you feel humiliated and/or guilty only because you two haven't been having sex in years (i.e. you think that if the two of you were having sex, he wouldn't be watching porn). And since you haven't had sex in "many, many years," as you put it, it sounds like the issue of your nonexistent sex life has only become an issue because of your discovery of him watching porn--that is, it isn't something that would have necessarily become an issue if you hadn't discovered porn on his computer. In your post, you don't express any kind of desire to have sex with him or say that you've been bothered or frustrated all these years by the lack of sex in your marriage--rather, it sounds like you're simply feeling guilty, like you haven't fulfilled your wifely "duties"/obligation and have thus made him turn to porn (porn being a bad thing, in your view).

Maybe you two aren't having sex for the simple reason that you don't want to with each other. This is normal. Promising to only be attracted to your spouse for the rest of your life is crazy. But if you plan to stay together, then you might want to see a marriage counselor about this to help you reconnect sexually with each other. Or just get used to him watching porn and don't think of it as a bad thing.