Other than to smear a potential Republican presidential nominee (which is, of course, the point), I fail to understand why this is a news story at this time.
I suppose it could be a cautionary tale to illustrate that, if you're the "other woman," you shouldn't be surprised when your husband later decides to trade up.
Or it could just be to demonstrate to the Secretary of State how a self-respecting woman responds when her husband is catting around.