T.H.
I had the same problem. there are a few different ways to approach this. either way involves talking to him about it. if you can't communicate then you don't have a good relationship.
1. offer to look at the "material" with him. even if you don't like certain things. he will see you are making the effort.
2. spice things up in the bedroom. do something you wouldn't ordinarilly do that you know he likes. keep him interested.
if you can do these sort of things or be spontaneously romantic then he should come around if he doesn't then i am sorry to say you need to be blunt. tell him it bothers you and that if he is going to look at that sort of thing to please do it when you are not home and not to save it to the computer. you need to understand though we females have many "toys" available to us and men don't always have that option and as long as he spends equal time with you i wouldn't be too worried. at least he is not cheating on you with another person he is trying to prevent that which means he at least cares for you. either way let him know how you feel and that it needs to not be done when you are at home and can help him out.