While in the JW organization, how often did we hear "marriage is a 3-fold cord"? Man, woman and Jehovah, right?
The organization really is the third strand. I heard it said that if you chose a mate who loved "Jehovah" more than they loved you, your marriage would work out just fine. So that loyalty to their organization was supposed to be a factor in determining the suitability of a prospective mate.
The husband should go on to become an elder and sacrifice hours and hours of precious time to their congregational duties, and this was a way of showing they loved "Jehovah" the most.
If a mate didn't live up to "Jehovah's" standards, it is possible that one who loved "Jehovah" more than they loved their mate would report such transgressions to the organization for "correction".
I don't see the 3-fold cord as described by the Watchtower literature as an advantage, unless both mates are most interesting in keeping a certain status within the organization. For those kind of people, perhaps it was an advantage.