Sanctification and sin

I used to think that the motivation to try not to sin again is because we don't want to crucify Jesus at the cross again with our sinful thought, speech and action. But, in my experience, sin occurs naturally within us because of our sinful nature. Even if we are able to control our speech and action, sinful thoughts still occur. Our love for Jesus is not vast enough to prevent us from sinning or else we will be trying to be God. So, I guess we have to acknowledge the reality of our fallen nature, not to think that Jesus is not able to withstand our sins again and again, not because we want it but we cannot help it. And finally, we have to repent  again and again once we sin again and again.  Don't get me wrong, we should exercise self control in speech and action but my point is we cannot exercise self control in thoughts because they occur naturally.