If a politician seeks office with a detailed platform, and keeps to the issues at hand in the election, taxes, spending, policy, etc.
Then that politician's private life is pretty much out of bounds.
If a politician talks about their family, their religion, their moral values as a part of their stump speech, then that politician's family, their religion and their moral values are on the table.
There are the obligatory family portraits, the spouse and kids on stage at the acceptance of the nomination, which happen, but I don't think bring the family full tilt into the campaign.
It's when a politician makes "moral values" an issue that that politician makes their own moral values an issue.
If you want to claim to be the candidate for "family values" then don't shack up with Hootchy-Kootchy Hot Argentinian news honeys.
If you want to hold up your family as an example of "family values", then don't be outraged when someone brings up that while Mom was busy being Governor and Dad was off racing snow machines, Junior was doing Oxycontin, and Sis was boinkin' half the town, and where was Mom and Dad's family values then.

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“ The subjects of every state ought to contribute towards the support of the government, as nearly as possible, in proportion to their respective abilities; that is, in proportion to the revenue which they respectively enjoy under the protection of the state.”

Adam Smith , The Wealth of Nations 1776

"We have always known that heedless self-interest was bad morals; we know now that it is bad economics"
FDR's second Inaugural Address