Do I confront him?

I recently noticed a payment on my fiancees credit card statement (which was left opened on the kitchen bench) for registration to and adult internet dating site. After seing this I opened an account myself with the same site and found his profile which says that he is looking to meet other women and couples "for discreet times". It also says that as he "works away from home it makes it easy to travel to have fun". I'm afraid that if I confront him about this he will be upset, and accuse me of snooping in his private business and not trusting him. I don't want to loose him, what should I do?