I've heard good things about the Retrouvaille workshop although my H and I did not attend.
My H and I were to go to an Imago workshop until my H decided he didn't want to work on our M and therefore we didn't go. We did however take Imago counselling back in 2003 and it was really good. It is what kept us together focused on the positive things in our M for the longest time. Unfortunately, we had stopped going after 4 months because my H thought we were on the right track and we didn't need to go anymore. I guess he was wrong.