Yes, it is true, both partners do not need to want to save the marriage to walk in the door to Retrouvaille. In fact, few couples do. There's always one spouse pulling, and the other going along because.....a lot of things. Children, usually. Retrouvaille believes the children are always worth the effort. That we owe it to our children to try.
Thinker, I see what you are saying, that you may only get one shot at it, but those aren't their rules. You can go back. I met couples there who had tried before and failed, and came back a year or two later when they had more understanding. Retrouvaille will ask you to really look inside yourself and see what you want in life. And reveal that to your spouse. And talk about it, in private. Just the two of you. No counselors, no third opinions. And yes, it works. Not for everyone. But probably for more than 1/2 the couples who walk through the doors.