I would think their affair is going to implode at some point; it would be a matter of when and not if they will break up at some point. Of course, if it's after the divorce that won't do me much good.
Karen,
Just statistically, that's HIGHLY likely. But not only will it not help YOUR marriage if it happens after the divorce, it's also true that if you EACH don't figure out how to deal with your issues, you will just take then into your NEXT failed relationship. Also true statistically.
That's the great, "win-win" thing about DBing and GAL stuff. Not only are they effective tools to try to SAVE a marriage, but worst-case they better equip you for your NEXT relationship.