If these are past sins which have already been confessed, then you need to let go and move forward and realize that you have been forgiven. If it is ongoing, you are not alone and the work is hard.
If we know something is wrong, then we must work hard every day to avoid falling into such a sin. What is pleasing to God is a full-hearted effort, as opposed to not trying at all or giving up on trying because it is too hard. First there must be a desire to turn away from sin and be willing to submit things you want, in order to be obedient to God’s will.
There are websites to help Catholics battle impure sins of addiction. Sins of impurity are high on the list of things that are brought out in confession. Addiction also mitigates culpability to some extent, but does not excuse the need to please God by working at ending the addiction. This means giving other things up that lead up to the impulses. It could be a favorite TV program, or a friend, or other things that get you into temptation.
Best wishes and never give up hope. Despair and hopelessness are seeds of the devil and he hopes they will sprout into a rejection of God’s love and mercy. God’s love is unconditional and we experience God’s mercy through confession. When it comes to addiction, the best thing to do is to find a priest you are comfortable talking to, tell him you have an addiction and want to turn it around. You can do this from behind a screen or face-to-face. You can do this in your own parish, or find a priest in another parish, or find a priest from a local monastery. They will tell you to come back weekly for confession until it is under control. And, it will get under control. Just read through some of the sites that are provided in this thread.
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