I suspect that once the "little page boy" knew, Lord Whatsis knew the story would get out, and HAD to 'defend his honor'....but killing wives is not always convenient. He may not have a clue where he'd get another, and SHE probably knew she'd be 'safe', even if she mocked her husband.

You can bet there are 'marriages of convenience' not much different today....not ALL involving murder...but....