Just because you do something doesn't mean you like it.
Romans 7:21-25
New International Version (NIV)
21 So I find this law at work: Although I want to do good, evil is right there with me. 22 For in my inner being I delight in Gods law; 23 but I see another law at work in me, waging war against the law of my mind and making me a prisoner of the law of sin at work within me. 24 What a wretched man I am! Who will rescue me from this body that is subject to death? 25 Thanks be to God, who delivers me through Jesus Christ our Lord!
So then, I myself in my mind am a slave to Gods law, but in my sinful nature[
a] a slave to the law of sin.
I love that verse. You want to do right, but can't, but thank God for Jesus Christ. Everyone sins, and once is enough to send someone to hell. But accepting Jesus is enough to cancel all those sins. A lustful thought, even if it absolutely horrible is still sin. Jesus' blood covers sin, period.