The answer
The sin that is troubling you is not uncommon for a young man at your age. This does not justify your actions, but it is an attempt to explain to you that every phase in life has certain temptations that are more likely to result in certain sin more than at other times. At 21, you are full of energy and have much freedom, i.e., your parents are not guarding your computer or your whereabouts, and you probably do not have filters to block off this kind of nonsense. Therefore, the responsibility is on your shoulders and you must decide to be proactive. Begin by deleting any seductive sites, temporarily place filters as reminders, and place a religious picture as a screen saver. These are only cues to help you to remember, but they are not solutions. In the meantime, you need to release your energy in productive matters. Join a gym, volunteer somewhere, put in more hours at work, and/or take an extra course of study. Again, these are not solutions, but mere suggestions to help you begin to make changes in your lifestyle. Once you begin to decrease the times you engage in this sin, you will rather enjoy a new found freedom much more than being bound by your own thoughts and desires.Judas Iscariot fell in despair and could not admit his errors. St. Peter wept bitterly when he denied our Lord, but his repentance was accepted. So long as you do not lose hope or tire of confession regarding this repetitive sin or any other sin, God will accept your repentance and appreciate your struggles. The Lord is kind and merciful. He is not looking at your weaknesses to keep a score card. He patiently recognizes your efforts and your willingness to remain vigilant in your internal struggles. In the same manner as with married couples, refrain from partaking of the Holy Eucharist following an episode when you have engaged in any kind of sensual activity and/or fantasies. I would imagine that your confession father has probably already taken these measures with you for this reason. Perhaps, this will be an incentive to withdraw from this type of lustful sin. May the Lord help you to overcome all sin in your life and strengthen you with His grace.
"Man is born from man, being subject to passions from a being subject to passions, a sinner from a sinner. Thus sin takes its rise in us as we are born; it grows with us and keeps us company until life's end. Meekness has its source in humility. In banishing pride from the heart, we have no more occasions for anger, no more of the false refinements which so strongly make us feel the offenses committed against us.” (St. Gregory of Nyssa).
Answered by His Eminence Metropolitan Youssef (opens in a new tab)