One wire comes in from the power source, and one wire goes out to the light(s). A 3-way switch adds two terminals for travelers, which connect two 3-way switches together.

In some (all?) variations of a three way switch, either of two wires MAY be hot. if you are using Black/White wire, no combination is 'right'. It would be up to you to mark the white wire so ...

To make the wiring work flawlessly, so your husband becomes a lover of these switches, you install the same special three-wire cable in between all the three- and four-way switches in the circuit.

One wire comes in from the power source, and one wire goes out to the light(s). A 3-way switch adds two terminals for travelers, which connect two 3-way switches together.