Speaking of open marriages?

... Or is it possible there’s something else going on here? From a reader: “For over six years, my husband and I have been ‘best couple friends’ with another couple (unmarried, but they own a house together, etc.). They join us on vacation, we eat over each other’s houses frequently, we considered them to be wonderful people.

”Recently, they have apparently added a third person to their relationship, a very young woman. They include her in their dinner parties, and now want us to invite her along to our house.

”We are both totally grossed out, and don’t want this third party anywhere near us! How do we tell them? Are we prudes? Or are they totally insane?!”

What would you do in this situation?

— Carolyn Hax

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