Dear Grandparenting: My son is married but sure doesn’t act like it. Same goes for his wife. Both run around. How much, I don’t know. That’s their business.

I do know this has been going on for some time. And I do make it my business to keep up with my grandchildren, ages 13, 12 and 10, three pawns in the crazy game their parents play out in front of them. I am ashamed to have raised a son like that. All the cheating hasn’t made anyone happier either. You can cut the tension with a knife.

My son is too far gone but the grandkids need rescue. That’s where I can make a difference and take them in, and I’m up to the job. Even if my cheating son and his witch of a wife go along with it, the kids might veto my idea. What would you do? Mimi N., Jacksonville, Florida

Dear Mimi: Somewhere there must be children from an open marriage who are happily married, well-adjusted adults, but then again we’re still waiting to meet one.

Slipping the marital bonds for hookups and affairs is like a mad scientist running multiple experiments simultaneously. One cannot predict what will happen, control all the variables.

Marriage is an experiment too in a sense, and so are children. Parents add ingredients like love and safekeeping and hope for the best.

But this is one experiment you cannot re-do when it fails, and marriage between two footloose parents is a recipe for disaster, with harmful short and long-term consequences for children that can sabotage their potential and relationships.

Given the circumstances, we would step up and take a more active grandparenting role, including care and feeding. Instead of feeling ashamed, you can feel proud to have made a real and lasting difference.

Grand remark of the week

Trish Hassenhauer from Albion, Michigan reports that her eight grandchildren “know the magic words.”

“My grandchildren are as different as can be. They live in different states, have different interests and range in age. But all eight know what I expect, just a simple ‘please’ and ‘thank you.’”