My boyfriend still has pictures/videos of his ex-wife...?

I understand that everyone has a past and that it was before me, etc. - However, I found out he still frequently looks at them as well as inappropriate photos of other girls he once dated. I found a hidden and locked folder containing nearly 50 pics and videos. I'm disgusted, pissed-off and saddened by his behavior. I know if I confront him with it, rather than admit he's wrong, he'll tell me that I shouldn't have been "snooping" (even though it's a family computer) and that it doesn't matter. What should I do?