What to do about that besetting sin? Ed Welch summarizes:
We will all sin again, of that we can be sure. When we do, we ask forgiveness of both the Lord and those who were wronged. Then some hand-to-hand combat against sin is probably in order along with some public planning to either stand firm or run when there is another assault. All of this is both preceded and followed by our rest in forgiveness of sin secured by Jesus. Rest is spiritual, complacency sinful.
For more on battling a besetting sin read the rest of When You Are Planning to Sin Again