Dear ###
As what ### said is very valid indeed. You need to get some sort of accountability from a fellow brother who is spiritually matured or from your pastor (I hope you are attending church).
Accountability is where you share your problems and get prayed by your pastor or a fellow brother and usually they will also do give you some Bible studies where you can have with them every day. Keep yourself occupied with this sort of fellowship daily will help you greatly.
The other thing is get some sort of software that helps you to block off those kinds of sites. I think there is another one too that is called "Nanny."
Also you need the Word (reading the Bible) every day so that your mind can be renewed and cleansed—but you need to read it daily. How desperate you are is how much you desperately make yourself to read the Word daily. The Word is like water where you use it to wash off that stinking mud and dirt off yourself.
Here are some of His promises that you can claim, read and ponder upon deeply :-
Job 31
1 “I have made a covenant with my eyes;
Why then should I look upon a young woman?
Proverbs 4:25-27 (New King James Version)
25 Let your eyes look straight ahead,
And your eyelids look right before you.
26 Ponder the path of your feet,
And let all your ways be established.
27 Do not turn to the right or the left;
Remove your foot from evil.
John 14:14-18 (New King James Version)
14 If you ask[a] anything in My name, I will do it.
15 “If you love Me, keep My commandments. 16 And I will pray the Father, and He will give you another Helper, that He may abide with you forever— 17 the Spirit of truth, whom the world cannot receive, because it neither sees Him nor knows Him; but you know Him, for He dwells with you and will be in you. 18 I will not leave you orphans; I will come to you. Amen, In Jesus' Name we give thanks and praise for ###'s victory.
Also we pray that You will send him the right kind of fellowship and accountability that he needs to have as we ask this in Your most precious Name, Jesus, amen-###