Exactly. This is the right approach to this situation. Calm, learning curve, discussion, recognition of the differences between males and females when it comes to sexual arousal patterns (which may mean staying away from water parks if they create too great a problem for a man–too bad), and agreeing on behaviors.
Yes, the OP tried–at the wrong time. You don’t “discuss” anything when you are upset, angry, disturbed, etc. You wait until the more opportune moment. A lot of marriages could be helped by following this principle.
And this is not going to be solved by a one-time discussion in which the husband becomes “mature”. This will be an ongoing issue for this couple for the rest of their marriage, just as it is in all marriages. Attitudes towards sex and various sexual behaviors will come up over and over again, and the couple must continue to work TOGETHER constantly to be at a place where they are glorifying God, edifying each other, and contributing to a wholesome society/culture in their sex life.
By the way, I do not consider a waterpark a “porn situation.” The husband didn’t spend 6 hours “watching porn.” He spent six hours surrounded by women, teenagers, and children wearing swimsuits–yes, they reveal flesh, but that is NOT porn!!! And people on this thread say I’m going over the top on this question?!