Catching your partner watching porn on the Internet or televsion can be shocking. It is hard to know what to say, while the initial reaction may be anger. However, that may not be the best option. First know you are not alone, adult pay per view brings in a lot of money, which means that there are a lot of others watching it. Not just your partner.
Remain calm, do not embarrass or belittle your partner. Talk about it and let him or her know how you feel, and listen to what he or she says about their reasons for watching. As long as it is not interfering with every day life and not putting a big strain on the relationship, it may be best to not make a big deal out if it. It may even be something that you can watch together to spice things up a bit.