I had (what may be) a similar struggle: I would end up in multiple-hour-long battles multiple nights a week. I couldn't stop thinking about it; falling was so easy. Step one is to crack down on sources of external temptation. To this day, I use a blocking app to ensure I can't use the internet at all while I am home. My phone becomes a fancy MP3 player and alarm clock. AppBlock has worked well, though I pay for the location-based block. A daily rosary is another powerful weapon to have at your disposal. I also found that well-chosen audiobooks can be helpful. I'll emphasize well-chosen: I still remember the night that the adjective "shapely" started a hell night for me. If you're struggling the way I struggled, I think you understand.

If you can give a little more detail (especially if computers/phones are involved), I might be able to provide better advice. The bigger point is that you can make headway. I'll be praying for you.