I have a confession.

I was unfaithful once — well, twice. Since I’m confessing, I ought to be honest.

This confession is South Carolina Gov. Mark Sanford’s fault. Sanford cheated on his wife.

As you’ve heard, Sanford, once a probable presidential candidate, pretended to go hiking and instead traveled to Argentina for illicit “luuuuv.”

He returned repentant — i.e., he knew the jig was up — and he came clean.

The jig isn’t up with me. I’m honestly repentant.

When I was growing up, my mother made me promise I wouldn’t go to B-rated movies and I wouldn’t enter a den of iniquity.

But one night when I was a teenager, I told my mother I was going to a dance, and instead, I went to see “Barbarella,” a Jane Fonda film, which contained much nudity — not according to today’s standards, but it was risqué.

As if that wasn’t bad enough, a friend Jerry and I caught a bus for Kansas City one night in order to sneak into a strip club. Jerry got cold feet, though, called his dad, who came and drove us home. All the way, I listened to Jerry’s dad tell how proud he was that his son resisted temptation.

I never mentioned those incidents to my mother. Some things are better left unsaid.

For instance, late in both their lives, my dad told my mom that he cheated on her. He listened to someone who said to go to the person you offended, even if they didn’t know you offended them, and ask forgiveness.

I don’t agree — ask God for forgiveness and go on if the other person isn’t aware of what you did. You were a jerk once. Don’t be a jerk twice in telling them what you did if you don’t have to.

Not that my dad was a big jerk, but sometimes silent diplomacy is best.

It was easy to forgive my dad. It really wasn’t an affair. He told me this woman he knew came in just before he closed his shop, and it just happened. He and my mother weren’t getting along, he dallied once with that woman, and that was it.

Unlike Sanford, my dad wasn’t delusional, thinking the new woman was the love of his life, and he didn’t convince himself that his wife was a mistake. He didn’t concoct lies to satisfy his prurient desires. He was sensible enough to know, even in his weak moment, how it would hurt his family. He wasn’t like Sanford, and he wasn’t like Presidents Clinton or Kennedy, who delighted in seeing how many women they could conquer.