The practice is often called "wife exchange," but more logically it should be "husband exchange" since it was almost always the husbands who changed places.
The exchange might last any length of time, with a week or so being typical.
But did they offer that privilege to any horny schmuck who showed up on the front stoop? The lending of wives to perfect strangers happened occasionally in some places, but it was never the widespread custom it has been made out to be.
There were several contexts in which a husband would let another man sleep with his wife.
This was a sort of combination of seven minutes in heaven, Roman orgy, and prayer meeting.
The prayer-meeting aspect failed to overcome the objections of the early Christian missionaries, one of whom called it the "whore game." Those guys really know how to ruin a party.
One example from Alaska was called the "bladder feast," which sounds a bit less appetizing.