indiscretion - a petty misdeed peccadillo misbehavior, misbehaviour, misdeed - improper or wicked or immoral behavior
If you think divorce is an indiscretion, then vote for Hillary. She's never been divorced.
You said it -- Rudy running around in public with his mistress while his wife (#2) was at home with the kids. Improper, wicked and immoral behavior.