3 couples on one side of a river. Aa Bb Cc (caps representing husbands, lowercase representing wives)
One boat in which 2 people can travel at a time.
At least one person must row the boat wherever it needs to be taken. The boat cannot travel to any side by water current.
People can travel with someone of the other gender only if they are their spouse. No man or woman can travel with someone they are not married with. (This is what makes this puzzle different from $n$ couples crossing a river)
No woman can be left on a side with another man unless her husband is also present there.
What is the method for all of them crossing the river?