World Wide Marriage Encounter is not affiliated with any religion in particular, although each weekend usually is focused around a specific religion. So, for instance, the weekend I went on had 8 speakers, 3 married couples, one priest, and one nun. Everyone who attended was Catholic, and it was opened to only 3 parishes in our area.
The next weekend was going to be the Jewish WWME with a rabbi instead of a priest as a speaker, and targetting Jewish couples. They also have non-denominational Christian weekends, and secular weekends.
It is important that you attend the “Catholic” weekend in your area. I don’t want to give too much away. You will not be disappointed in this weekend, I promise. You can not learn this in a university communications class, or by reading a book. Just go.