So my wife and I survived leaving the JW faith together over the course of the last 4 years. It was a wild ride for our relationship, but thankfully we are stronger than ever. So looking back, here is my observation about the "threefold cord", at least the JW version of it.
I believe the idea of the threefold cord actually weakens a marriage, keeping it less mature. The theory is that with Jehovah in your marriage, it will strengthen your marriage and keep it stronger. However, having Jehovah in your marriage can very much be a crutch, and I've seen more unhealthy marriages within the JW faith than out. Couples that are just miserably together. Given you cannot (or should not) divorce, and with the promise of a perfect paradise around the corner, pressures to keep a positive looking front, etc, it is very easy to ignore marital issues and sweep them under the rug.
Jehovah (i.e. the organization) comes first in the marriage, and there's where your loyalty is supposed to be first. I've heard people say (not sure if I've seen it in writing) that you cannot love your spouse unless they love Jehovah first. Now talk about introducing a serious flaw in to the marriage! Without that third fold, the other two folds, the couple, are weaker than they would be if they were standing up on their own.
When we left the faith, we lost that crutch. It was just us two, all of a sudden with no one to moderate, or force us to stay married. Our relationship and marriage had to mature to stand on its own, and we had to deal with issues that have been swept under the rug. Divorce was an option, and no longer could we just ignore things while enduring for the new system. That's hard work, and takes dedication. I can see how leaving the JW faith can cause divorce, because when your relationsip rests on the crutch of Jehovah (the organization), you lose that crutch, and risk falling apart.
I'm not saying having spirituality within the marriage is necessarily a crutch (I'm Atheist however), but the JW brand of the threefold cord is NOT healthy, it keeps marriages immature, and only forces the couple to lean on the organization to survive. Maybe that's by design.
Any thoughts? Observations? Experiences?