My husband and I went to one last summer. It boils down to both of you daily getting in touch with and expressing your feelings to each other without judgment. A lot of communication problems in marriage and hurt feelings come from not expressing them and/or not being heard by your partner.
We do not “do” (and never did) their techniques after the weekend. However, the work that you do over the weekend opens you up about things that you would not otherwise talk about, serious issues and emotions. We did a lot of crying, and snuggling.

It was an experience that we would do again. I think it’s always good to continually get into the meat and potatoes of your marriage like that.
Word of caution though… Our experience as far as the Mass was AWFUL. There were a number of illicit things going on, like no kneeling at consecration, readings not done according to the rubrics, prayers of the faithful open to what anyone wanted to shout out (and one woman asked us to prayer for a friend who was having in-vitro that it would be successful)… Yeah, when we go again (which I’m sure we will), we will skip all masses and go to a local church. That type of thing will depend on your particular encounter, though.
I also found the communal meals long and irritating, but I am a natural introvert and don’t like being around people I don’t know in that kind of situation.
Go, dig into your marriage, take the good, leave the bad. In the end, it was really worth it.