Start meditating. Its not a quick fix it will take time and u need to progressively up ur game in it as well. but u'll start noticing ur mind sabotage u and learn to control ur thoughts. Basically u'll be able to control ur arousing images and temptations to look at any arousal images or fantasies. Personally it took me a month to start recognizing my thought pattern and have some control when my mind started fantasising. give it a good 3 months of normal meditation DAILY 20 min and some cardio or whatever exercise u want to do, if it dosent work screw it, but be committed 100% EVERY SINGLE DAY. NO RATIONALISING. NO EXCUSES.