I dont think this is any reflection on Joe's character...he just had the guts to admit to it! If his wife doesnt care if he views porn then why should we? She must not feel threatened by it. If only we could all boast of being that secure. Very open-minded I'd say. Besides, we all have our guilty pleasures, do we not?
Its also occured to me that Joe might just be playing "devil's advocate" here and he really doesnt care one way or another.