However, a man who is starving to death would see a garbage can as a feast. Similarly, a man who is filled with unconditional love has the greatest prize in the world. He's happy all the time. But a man who feels unloved is starving, as literally as a man about to die from lack of food. To such a man, any kind of connection to other people, any kind of excitement, feels better than nothing.
Pornography provides a brief distraction from the emptiness in that man's life.
The solution is not to confront him about the pornography. If you forced him to stop that, he would satisfy his need for Imitation Love in other ways, perhaps more harmful. You clearly have not provided that for him, or he wouldn't be looking for excitement elsewhere. But don't feel guilty. The answer is to get Real Love for yourself, and as you get it, you'll have something to share with him.