One of the first theaters that I knew of that had regular action with couples was the Mel in the city of Melvindale, Michigan, a suburb of Detroit. They used to have couples nights during the week, allowing couples to attend for free. Those were the nights I would try to drop in whenever I was in the area.
Like a lot of other porn houses in the 70's and 80's, the Mel was an old theater, built in the 40's at a cost of $250,000! It had style and for many years was the center of community life in the Melvindale, even hosting the local high school graduations. As movie-goers headed to the mall and the multiplex theater, the Mel, like so many others, began losing money. Until they turned to porn.