I've heard this sort of nonsense ... I attended such a retreat as this back in the '70s. I would have hoped that they had gone the way of the dodo bird by now.
Oddly enough, my 'Engaged Encounter' retreat, 'way back when, in the Dreadful Diocese of Richmond, no less, was sane and very useful.
My wife and I (engaged at the time) left halfway through the weekend - about the time her roommate asked if she could switch rooms with me and sleep with her fiance, and just after the deacon running the program refused to correct couples from promoting pre-nuptial agreements and co-habitation (during a group discussion).