I suggest communication. How do you feel about where the relationship between you two is going? What would you like to see, and what would he like to see? Talk to each other. Listen to each other. Something that goes a little further than "why do you watch this" and "I like it". If he's ready to drop anything he's doing with you to spend time with people who make porn he likes, what do you think of that? How does he see this? Did he even know this is a problem for you? What danger do you two think it could this pose? Do you feel like your relationship with him has been damaged by this? How much? What does he think about this? How do you two want to make it healthy again together? Think about all of this. Discuss it with him. Important relationship stuff. You can even consider taking couple's therapy to talk things through with him.
Romantic relationships are very complicated. That's why this is so important. So I suggest you do that when it's appropriate to do so. And if you don't want to talk or can't talk because of the damage between you two? Take some distance and find a creative way to discuss. Agree on a way that works for you two together. You could give each other a letter. Use paper airplanes with the message. Record yourselves and speak in the camera, and then show each other the video you both made. Whatever works for you two. As long as you two are communicating, and consider each other's viewpoint.
You might also need to think about how far you want to go to stay in this relationship, if it ends up coming down to that. And you made it sound like it is, in this case. Are you willing to wait until he breaks it up? Do you want to break it off when you don't see a change in either of you? How long are you willing to wait and how much work do you want to put into fixing things? How often do you want to voice the same concerns? How much damage does your relationship need to have for you to leave the relationship behind? Are you willing to stay with him if he genuinely wants and tries to fix this, but can't? You don't have to say this out loud to anyone. These are questions only you can answer.
Don't sit around doing nothing, just waiting to see where the relationship goes. You also shouldn't break the relationship off because of a little damage, especially if you haven't tried to work things out together yet. So try to fix it with him. But for your own sake, also don't stay in a badly damaged relationship for too long if he is not willing to fix at least some of the damage together with you, or it might end up damaging you (or potentially even both of you).
Also very important, don't try to damage the relationship even further to bring you two back together. Things like giving someone a silent treatment has a huge potential to severely increase the speed at which your relationship is getting damaged, and it increases the potential of breaking the relationship entirely. Don't do it. And keep in mind that if any question is answered by "I don't know" by either of you, that's fine, as long as you have thought about the answer. But you don't have to take it as an answer if you are certain that he hasn't thought about it. Your boyfriend needs to talk and listen back as well.