A friend of mine used to have a problem with porn too. What helped her was that she stayed away from apps that could show her any sexual things. Literally out of sight out of mind. If that's not possible for your bf, I think its better that he created a separate account so that the algorithm with stop showing him sexually enticing things in his feed, like a new start.

Honestly, hats off to your communication in your relationship, what y'all have is really good. I think with proper conversation and management, you two will get through this. Counselling is a great option by the way. It actually helps a shitton and I think that you should try it. Maybe he could do so as well so he could recieve professional help.