Your sinning with porn is a result of your free will and the Lord won't stop you. You have to make the decision on your own and then you can communicate it in a prayer. Few weeks before Easter I promised to Jesus that I won't sin (PMO) during the Holy Week. On Palm Sunday I was already further in my development and fully submitted my life to the Lord in an obedience prayer. This was the day my NoPMO streak started with a 40 days long flatline. And then the whole train started rolling.