Porn is a bad modern thing and anyone in a relationship shouldn�t be looking at porn they should show the love for each other and then express their love through intimacy. It is really unconstructive in a relationship to be watching porn. Although once on it, it can be really hard to get off it. It�s an addiction like many other addictions and its quite hard to stop. What I do recommend is try talking to him about it when he is relaxed and you think he�ll have an open mind, or take a break, maybe a weekend away (without any internet access) and then a couple of days into the break talk to each other about how nice it is to have a nice time together (without any external influences) and just to be focused on each other and nothing else, and that�s how things should be the whole time etc. Hopefully this will get you�re relationship and back on track and if it does you�ll see big improvements in the bedroom too
If you do take a break make sure he isnt board because if he�s board he�ll just be thinking of porn.