King Henry VIII executed two of his wives for alleged adultery. This was almost certainly true of one of them, Catherine Howard, while the facts concerning the other one, Anne Boleyn, are in dispute.
When King Christian VIII of Denmark married Princess Caroline of Great Britain, as detailed in the movie "A Royal Affair,", the queen's affair with the court doctor (and royal adviser), Struensee led to the man's overthrow and execution.
In a third situation, Isabella, the wife of King Edward II had an affair with Mortimer that resulted in the overthrow and (probable) murder of the king by his wife and lover.
As a commenter pointed out, a queen's adultery would likely threaten the succession, with potentially serious consequences for the country.
Are there any "well known" cases in history where it was established that queen consort of a king slept with someone other than her husband, and no one was executed, or was known to get into serious trouble as a result? If so, what were the circumstances that prevented bad consequences? Put another way, why might the threat to the succession or to the country not seem to matter, in such cases?
(A "queen consort" is a the wife of a king. Queen Victoria, who allegedly had some affairs after Prince Albert died, is not in this category. Elizabeth I was known as the "Virgin Queen.")