you told him you would leave him if he continued, and here it is 2 years later and he hasn't stop but you are still with him. he is getting away with something you told him bothers you because you haven't followed through on your threat of leaving.

believe me, i know how hard it is to leave someone you love, but idle threats do not work obviously. tell him since he hasn't honored your wishes you are taking a break from the relationship and do it! cut off all contact for a couple of weeks or a month. give him time to think about what is more important to him, you or the porn. if he chooses the later, i think you know what you have to do.

good luck.