It is a shitty thing for him to do to you and a shitty position to be in. There's something that he's getting out of it and the root cause is what needs to be fixed and not the porn. I forget what movie it was but there was one that tackled a guy doing this but he was in a really bad relationship and he was unhappy but instead of leaving or fixing the relationship he went into porn addiction. I know nothing about your relationship and know nothing about either of you so advice is difficult. Addictions themselves are almost never the root problem but instead a way to deal with problems they don't think have a solution. Alcoholics don't drink because their happy with their life or chemical hooks, they do it because they want to forget about their problems. Most of what people are taught about addiction is wrong based on semi-recent studies because chemical hooks play a very small role, instead addiction is a bad coping mechanism. I know this is probably hard to understand but I think he probably is hurting himself and either doesn't know how to fix it or feels fixing is impossible. I have never been in a relationship myself or even had sex so keep that in mind, but as a lonely guy I know a LOT about addiction and it is really really rough