And the king commanded, and those men who had maliciously accused Daniel were brought and cast into the den of lions—they, their children, and their wives. And before they reached the bottom of the den, the lions overpowered them and broke all their bones in pieces. (Daniel 6:24; ESV)I realize that this is a gruesome ending, and it doesn't seem to be fair to punish the men's families as well, but what this does illustrate is that our sin never affects only us. Our sin always affects those around us, especially those that are closest to us.
Think about how your sin, even if it seems to be secret affects those around you. At the very least it builds a wall of deceit between you and your loved ones as you try to hide your sin and lie about what you are doing.
When I sin I hurt other people. I hurt those that are close to me. I hurt those that I am not able to effectively reach out to, and I hurt God. Sin always has consequences, and they are never just personal. Our sin hurts other people.