New Problem:

There are two married couples that need to cross a river. A small boat is available that will hold just two people at a time. The males involve are quite jealous. No woman can be left with a man unless her husband is also present. There are no other constraints, though. How can these four people cross the river.

Even challanging, what is the fewestnumber of trips possible?

This problem is not hard enough; I will "update" this question after I get the correct solution to this one.

Happy solving! :)