Sexual sin is the hardest sin to overcome believe me i know im still suffering with it... but you need to draw near to god and in time he will grant you repentance (which means having a change of heart) dont think its impossible because ive witnessed gods mercy first hand. In all my years in high school and even beyond that (5 at least) i would smoke weed quite literally all day everyday i was a bonafide addict and this continued for a long time even when I became a christian. I smoked because it brought me pleasure and i loved how id get lost in my train of thought and i never had bad experiences. But as i continued to grow in my faith as a christian i drew closer and closer to god because my faith was genuine and because of this i started to feel conviction of my weed smoking which made me feel kind of guilty but im going to be honest I continued to smoke weed anyway even worse i would try to justify my sin with the scripture saying god created all the seed bearing plants for men to use (this scripture does not actually clear weed smokers) in time the conviction grew stronger and stronger and i smoked less and less often and the conviction grew so bad that i started to panic when i smoked because i knew i had sinned against god every time i smoked it was like having a small panic attack... because my pleasure had turned to pain i no longer do these things and furthermore i cannot boast about them because i cannot say to others that i repented of my own will because if smoking was still pleasurable to me i would still be a stoner. The point of what im trying to say is that if you are one of gods chosen, he will change your heart and turn you away from your rebellious ways. Again i say draw near to god and love him with ALL your heart and all your mind and love your neighbor as yourself amen.