Yes, Heartborken is right. It depends on the Retrouvaille group. There is a lot written on retrouvaille if you go into the search function and search under the keyword Retrouvaille for the last 6 months, you will have an afternoon's worth of reading.
I cannot recommend it highly enough. It changed our lives. It does not work for everyone, but it has a very high success rate. I believe well over 50%. The Post sessions are very valuable too. But the weekend by itself is tremendous. If she is willing to go, by all means do it. No matter what the future holds for you, you will get along better if you put into practice what they teach you over the weekend.