What happens in your life when you get off track? When your particular weaknesses lead you from the straight path?
If you make a practice of reflecting on these situations, you can see God's hand in them to chasten you and draw you back. If you do not come back, you are not one of His.
It should be a joy to know that God will provide fatherly discipline to keep you in His hand. It is not in your power to keep yourself - if it weren't for the work of the Spirit you would self destruct in sinful indulgence.
It should also be a joy to know that God is at work in you to reduce your wanderings, making you less sinful and more Christ-like.